- Auto-completion for character names in mail, chat, and pop-up interfaces can now be enabled (and disabled) from the interface options. I believe auto-complete was already in there for mail, but now it'll be everywhere, and/or you'll be able to turn it off if you've sent things to the wrong place in the past.
- Names are getting a color option according to class, so if "Lolpaladins" is really a Death Knight, you'll know right away.
- Casting bars near a portrait's target will show whether the spell is interruptible or not. Some boss casts are not interruptible, so now you'll know with a glance.
- Druids will be able to see mana bars even while shape-shifted, which probably won't change gameplay much, but will be nice for bears and kitties.
- Item comparisons (like the ability to check other gear for slots while hovering over that gear) are now available everywhere -- hover over an item with Alt pressed to see what's currently equipped in that slot on your character.
- Macros and scripts can no longer target totems by name -- bye bye totem stompers.
- The quest log is getting a small revamp: it'll be "double-paned for more easily viewing quest information." We're not quite sure what that means (you'll be able to look at two quests at once? It'll break out the list of accepted quests into its own full-size window?), but we'll give you a look as soon as we see it on the PTR.
- Vendor prices will now be listed on items even if you're not at a vendor. This was a pretty common feature already, thanks to Auctioneer, but now it'll be built into the standard interface.
Patch 3.2 will bring about a new 5, 10, and 25 man instance to WoW, and usher in a new 40-man battleground called the Isle of Conquest. WoW.com will have you covered every step of the way, from extensive PTR coverage through the official live release. Check out WoW.com's Guide to Patch 3.2 for all the latest!