The health care bill we actually got is more similar to McCain's idea than Obama's, which cheeses me off given it's why I voted the way I did.
Obama hasn't done much on the economy that wasn't already in motion before he took office, and he's going to renew the Bush tax-cuts, just like McCain would. So, not much difference there.
We'd probably be slower in withdrawing from Iraq, but Obama hasn't issued an order ending DADT, he hasn't fixed the "enemy combatant" ******** that Guantanamo symbolizes (or Guantanamo for that matter), and off the top of my head I can't think of an actual issue he's acted on that McCain would have done differently.
Give me a strong primary candidate against Obama in 2012 and I'll vote for him/her.
eta:But hey! Despite being indistinguishable from their canditate on the issues, the Republicans tell me he's a far-left socialist, so I guess I got the candidate I really wanted after-all. Hey, and I didn't even think one was running at the time.