I went to Prague in May. I was only there for 3 days (was travelling all over europe), and I really liked it. The city is beautiful, but no one spoke english so we found that part hard.
The exchange rate was FANTASTIC, and we're on the CND dollar. So yeah, stuff is cheap but they do stuff in big numbers there so it takes some getting used to. (like, a bottle of pepsi or whatever is 50 krowns...blah blah blah)
Didn't get a chance to check out the party scence much, but a great DJ called DJ Preach (who's originally from MTL) went to play there, and from what I can tell the party scene is sick.
HAVE FUN!!