Good music for a party?!
Check out the top 40 list, the songs might be slightly over played but just make sure to have enough songs to last you the whole night so that people won't hear a popular song played twice at your party. Here is a few sites to check out with good music:
Also think about renting a DJ. That way you won't have to worry about music on top of everything else you have to plan for.
Have a great birthday.
Hope this helps(;
It all depends on what you like and what you think you friends might like. I am 20, and the best music for parties are techno, electro, dance, hip-hop, rnb, but i recommend mostly dance and techno, it will have all of you moving. Get good songs though, for example like, The Time (Dirty Bit) by Black Eyed Peas, listen to it and find music like that.
play something they can dance to like the cha cha slide (it doesn't have to be that, but a song like that, with dance moves) in case people don't dance on their own
of course, popular hit music is necessary for a party. without music birthday or other party is not entertaining.