It all depends on what kind of stuff your looking for. I mainly use 3 different P2P programs.
KaZaA is good for finding music.
mIRC is good for movies and misc. stuff. But you kinda have to know where to search. Took me a while to find a decent movie server. TMD-moviez is one of the best servers ive found so far.
Finally, I use a usenet program that searches through news groups. Its not really a P2P cause people have to post up the programs first before you can download them, but the servers are run by your isp, so its pretty fast. Also, the program you use depends on your internet provider. I have verizon dsl, so i use Xnews. News groups are the best if you wanna get the latest games. and when i say the latest games, i mean games that just came out. People posted up Prince of persia 2 days after it came out with the no CD crack and stuff. All you have to do is ask, and someone will probably upload the game in a day or two. The things they post usually stay up for about a week.