Seems to me that if you're only looking to shoot parties and other occassional events, then you don't even really need a D5000. I mean, I have it and so far I think it's the perfect body for me, but I try to shoot quite a bit, too. I bought mine for shooting my kiddo and will probably upgrade as he gets older.
But if you're only going to be shooting when you get bored, go for something like a D40. You can usually find them for about $400-$500 with the 18-55mm kit lens. THe only realy difference between the D40 and the D5000 is the 11-point AF feature that's also on the D90 IIRC. Other than that, the D5000 is more or less a D40 body with a swivel screen.
Otherwise, spend the money and snag the NewEgg deal Advan posted before it's gone. Then you won't feel the need to upgrade later on if you decide to start shooting more.