http://elitistjerks.com/f72/t37337-dual_wield_builds/
http://www.wowhead.com/?talent=jfchqh0cZG0exhxzR0oZfM0hxM
The points on blood are for RP, more crit, less threat, self-healing. Expertise is an issue, so all the way up to Veteran of the Third War.
Frost is up to Howling Blast and Killing Machine. The latter is triggered with auto-attacks, which a dual wield has in spades.
Unholy is buffs up to Necrosis and BCB, which are also auto-attack triggered.
Dual-wield tank in mind? Better get that Expertise up:
Assuming 6.5% dodge and 15% parry, a player would need 26 expertise (about 102 expertise rating - 101.92 exactly) to negate a boss' dodge chance, and 60 expertise (roughly 236 expertise rating) to prevent parries.
To "cap" expertise against a raid boss, melee DPS need only concern themselves with the boss' dodge chance, provided that they attack from behind. This dictates a goal of 102 expertise rating, which is reasonably achievable given the gear added to the game in Patch 2.4. Tanks, however, attack from the front, and need to worry about both dodge and parry. As of Patch 2.4 it is actually possible to become unparryable as a tank.