Guardians of the Galaxy is the best Marvel movie since the original Iron Man, in my eyes. Great characters, light-hearted fun, and awesome ties to the Marvel Cinematic Universe. Exodus nailed it for me--this felt like the best Star Wars movie since ROTJ.
Pratt, Cooper, and especially Batista were great. Saldana was by-the-book, but obviously dayum-looking. This is coming from someone unfamiliar with the comics, but I'm definitely picking up some issues now. They're dirt cheap right now.
I really hope some aspects and characters of Guardians makes their way into Avengers 2. Pratt with RDJ would be comedy gold.