Here are a few of my favorite things;
in-app purchasing (think renewing subscriptions)
stereo bluetooth (A2DP)
search across all (or almost all) data in the phone
All in all, cool stuff! Developers can get their hands on 3.0 right now (or as soon as the dev site comes back!). To be released in “this summer”. Free to iPhone users, $9.95 for iPod touch (boo!!).