I highly recommend reading Mihir's excellent Cat Guide. To summarize Feral Cat DPS attribute priority is, generally: Agility>Strength*>Mastery>Critical Strike (to the critical strike soft cap)>Critical Strike (beyond the critical strike soft cap)≈Haste≈Expertise≈Hit
* Please note that while Strength confers significant Attack Power it doesn't offer critical strike. As a result, unless a Strength-based item is significantly better than an Agility-based item then Agility is far better.
Please see Mew, the World of Warcraft Feral Druid DPS Model for specific advice.
It is notable that attribute conversions suffer steep penalties beyond level 85 and, as a result, Expertise, Haste and Hit may offer considerably more value for Feral Cats have difficulty maintaining their bleed uptime. This is a direct result of reduced energy regeneration and increased chance to miss.
Last edited by Purrfunctory; 2010-11-21 at 10:51 PM.