Most of you know I like crunching the numbers myself with new builds. When I am done, though, I talk to other folks to see if they are seeing the same results, or I check web sites for discussion. Following is a list of some good sites for all classes, compiled from friends and online acquaintances.
Death Knight
Elitist Jerks: Blood Tanking in 4.0.1 (http://elitistjerks.com/f72/t105485-cataclysm_dk_endgame_tanking_4_0_1_a/)
PwnWear: Blood Tanking Compendium (http://pwnwear.com/2010/10/11/dk-tank-4-0-1-answers/)
Elitist Jerks: Frost DPS | Cataclysm, You Found Me (http://elitistjerks.com/f72/t105701-frost_dps_cataclysm_you_found_me/)
Elitist Jerks: Unholy DPS | Cataclysm, All At Once (http://elitistjerks.com/f72/t105521-unholy_dps_cataclysm_all_once/)
Consider It: Blog by the EJ main theorycrafter/poster (http://considerit1.wordpress.com/)
DK Sim: Gear, Spec, Glyphs, and Rotation simulations (http://meliades.org/cataclysm/DKSIM.html)
Druid
Gray Matter: Moonkin Guide to Patch 4.0.1 (http://graymatterwow.blogspot.com/2010/10/moonkin-guide-to-patch-401.html)
Quieth's Quips: Moonkin Guide to 4.0 (http://qieths-quips.com/blog/2010/10/09/moonkin-guide-4-0/)
Relevart's Druid Reliquary: Moonkin Class Guide (http://www.relevarts-druid-reliquary.com/blog/?page_id=128)
Sunfyre's Nest: 4.0 Rotation and Glyphs (http://www.owlkin.org/cataclysm/4-0-cataclysm-dps-rotation-glyphs/)
Syrco-Owl: Moonkin in 4.0.1 (http://syrco.wordpress.com/2010/10/10/moonkin-in-4-0-1/)
The Fluid Druid: Kitty Dps in 4.0.1 (http://fluiddruid.net/2010/10/kitty-dps-in-4-0-1/)
Feral Aggression: 4.0.1 Kitty Primer (http://feralaggression.wordpress.com/2010/10/10/4-01-kitty-primer-what-you-need-to-know/)
Mew: Feral Druid DPS Analyzer (http://code.google.com/p/mew-wow-druid-model/)
Think Tank: The 4.0.1 Feral Specs, Glyphs, Gear post (http://wowthinktank.blogspot.com/2010/09/druidthe-401-specsgearglyph-post.html)
Allison Robert, WoW Insider: Bear Druids in Patch 4.0.1 (http://wow.joystiq.com/2010/09/21/shifting-perspectives-bear-druids-in-patch-4-0-1/)
Tree Bark Jacket: Tree Patch 4.0 Guide (http://treebarkjacket.com/patch-4-0-guide/)
Restokin: Resto Druid Healing Guide (http://www.restokin.com/resto-druid-healing-guide/)
Rank 4 Healing Touch: 4.0.1 Primer Resto Druid Basics and ICC 25 HM (http://r4healingtouch.wordpress.com/2010/10/01/4-0-1-primer-basics-and-icc25-hm/)
RestoDude: Resto Druid Guide New (http://restodude.blogspot.com/p/restodruid-guide-new.html)
Hunter
MMO Champ Forums: 4.0.1 Hunters (http://www.mmo-champion.com/threads/770793-4.0.1-Hunters)
The Brew Hall: Hunters Patch 4.0 Some Thing to Expect (http://thebrewhall.com/2010/09/28/patch-4-0-some-things-to-expect/)
Warcraft Hunters Union/WoW Insider: Scattered Shots: Prepare Your Hunter for Patch 4.0.1 (http://wow.joystiq.com/2010/10/07/scattered-shots-prepare-your-hunter-for-patch-4-0-1-launch/)
Warcraft Hunter's Union: Beastmastery Hunter Patch 4.0.1 Talents Rotation and Glyphs (http://www.warcrafthuntersunion.com/2010/10/bm-hunter-patch-4-0-1-talents-rotation-and-glyphs/)
Warcraft Hunter's Union: Marksman Hunter Patch 4.0.1 Talents Rotation and Glyphs (http://www.warcrafthuntersunion.com/2010/10/marksman-mm-hunter-patch-4-0-1-talents-rotation-and-glyphs/)
Marks-365: Marksman Talents in 4.0 (http://marks-365.morynne.com/?page_id=1573)
Warcraft Hunter's Union: Beastmastery Hunter Patch 4.0.1 Talents Rotation and Glyphs (http://www.warcrafthuntersunion.com/2010/10/survival-sv-hunter-patch-4-0-1-talents-rotation-and-glyphs/)
Pets: Warcraft Hunters' Union (http://www.warcrafthuntersunion.com/2010/10/cataclysm-hunter-pet-and-raid-buffs/)
Mage
Mana Obscura: The Mage 4.0 Compendium (http://www.manaobscura.com/2010/10/the-mage-4-0-compendium/)
TotalBiscuit: Arcane Video Guide (http://www.youtube.com/watch?v=DPVPPnXOPTE)
TotalBiscuit: Fire Video Guide (http://www.youtube.com/watch?feature=iv&v=LjhdJedV4-Q)
Great Balls of Fire: Fire Raiding Builds Video (http://doyoumindifiplay.blogspot.com/2010/10/video-fire-raiding-builds-in-cataclysm.html)
TotalBiscuit: Frost Video Guide (http://www.youtube.com/watch?v=V3HbjJcc1Oc)
Great Balls of Fire: Frost Raiding Builds Video (http://doyoumindifiplay.blogspot.com/2010/10/video-frost-raiding-builds-in-cataclysm.html)
Paladin
Kurn's Corner: What Holy Paladins Need to Know for 4.0.1 (http://kurn.apotheosis-now.com/?p=1425)
Blessing of KingsHoly Paladin Spec and Glyphs in 4.0.1 (http://blessingofkings.blogspot.com/2010/10/holy-paladin-spec-and-glyphs-in-401.html)
Righteous Defense: Everything You Need to Know about Prot and 4.0.1 (http://rhida.ch/2010/09/30/everything-you-need-to-know-about-prot-and-4-0-1-at-80/)
Ret Pally: Ret Pally 4.0: Holy Shift (http://retpally.livejournal.com/7767.html)
Priest
Dawn Moore, WoW Insider: Sp[iritual Guidance: Reforging, Gemming, and GCD Tactocs for 4.0.1 (http://wow.joystiq.com/2010/10/10/spiritual-guidance-reforging-gemming-and-gcd-tactics-for-4-0-1/)
Dawn Moore, WoW Insider: Spiritual Guidance: Finishing Wrath Raids as a 4.0.1 Healing Priest (http://wow.joystiq.com/2010/10/03/spiritual-guidance-finishing-wrath-raids-as-a-4-0-1-healing-pri/)
Tales of a Priest: 4.0 Survival Guide – Holy & Disc Specs, Glyphs, and More (http://talesofapriest.com/?p=1249)
Press H for Heals: Discipline 4.0.1 Guide (http://typehforheals.com/2010/10/06/discipline-4-0-1-guide/)
World of Matticus: Raiding Discipline for Priests in 4.0.1 (http://www.worldofmatticus.com/2010/09/14/raiding-discipline-specs-for-priests-in-the-cataclysm-4-0-1-patch/)
World of Matticus: Smite Healing with Atonement Spec (http://www.worldofmatticus.com/2010/10/04/smite-healing-with-the-atonement-spec/) (balls of granite required)
Shadowpriest.com Forums: The 4.0.1 Checklist (http://shadowpriest.com/viewtopic.php?f=66&t=29492)
Rogue
Elitist Jerks: 4.0.1 Rogue FAQ (http://elitistjerks.com/f78/t105659-4_0_1_rogue_faq/)
PVE Rogues: 4.0.1 Mutilate Talents (http://pverogues.blogspot.com/2010/10/401-level-80-mutilate-cataclysm-talent.html)
PVE Rogues: 4.0.1 Combat Talents (http://pverogues.blogspot.com/2010/09/401-level-80-cataclysm-combat-talent.html)
Elitist Jerks: Combat Spreadsheet 4.0.1 (http://elitistjerks.com/f78/t105387-combat_spreadsheet_4_0_1_a/)
Shaman
Myrddin: The Enhancement Shaman 4.0.1 (http://www.myrddin.de/2010/10/09/the-enhancement-shaman-4-0/)
Windfury, Enhancement: Are you ready for 4.0.1? (http://enhancementshaman.blogspot.com/2010/10/are-you-ready-for-401.html)
Totemspot: 4.0.1 The Elemental Guide (http://totemspot.com/2010/10/4-0-1-elemental-guide/)
Sarah Nichol, WoW Insider: Totem Talk: Elemental Shaman Changes for Patch 4.0.1 (http://wow.joystiq.com/2010/09/23/totem-talk-elemental-shaman-changes-for-patch-4-0-1/)
Life in Group 5: The Resto Shaman's Guide to 4.0.1 (http://lifeingroup5.com/?p=1460)
Flow: Patch 4.0 Resto Shaman Build Speculation (http://www.restoshamanflow.com/2010/09/17/patch-4-0-resto-shaman-build-speculation/)
Warlock
Optec: Cataclysm Warlock Changes Guide part 1 (http://www.youtube.com/watch?v=Gk6WUOKXjaQ)
Optec: Cataclysm Warlock Changes Guide part 2 (http://www.youtube.com/watch?v=yCuCTE7uF44)
The Warlock's Den: 4.0.1 Cata Destro Rotation Spec (http://wowmb.net/forums/f9/40215-4_0_1_cata_destro_rotation_spec/)
Undercity: 4.0.1 Destro Warlock Rotation (http://underct.com/2010/09/23/4-0-1-destruction-warlock-rotation-more/)
Forsaken Few Guild: Demonology in Cata (http://forsakenfew.guildomatic.com/forums/viewtopic.php?f=8&t=76)
Warrior
Got Warcraft? The Cataclysm Warrior Guide (http://www.gotwarcraft.com/cataclysm/classes/warrior/index.php)
Naithin: Fun in Games: Prot Warrioring at 80 in 4.0 (http://funingames.wordpress.com/2010/10/02/prot-warrioring-at-80-in-4-0/)
I will add that one should not take everything you read on EJ as gospel. I see lots of people parroting them as
the Bible of WoW, and that's not true. (Not that I have ever been banned from EJ for being a prick about pointing out people being wrong....)
For example, I just checked and see that some DK Blood builds include Scent of Blood. At level 80, in ICC gear, you rarely find yourself out of RP. So on and so on. Use the data there to build upon, or to verify your own data.
Edit:
I was asked by someone why not Scent of Blood when you have Runic Empowerment (for those of you not Death Knights:
QuoteRunic Empowerment Passive
When you use your Death Coil, Frost Strike, or Rune Strike ability, you have a 45% chance to activate a random fully depleted rune.
)
I have found I am usually Runic Power capped, so I opted for more threat with BCB. I may remove points from Crimson Scourge or elsewhere, but I doubt right now I will put points into SoB. More discussion can be had on the DK forum.