Direct Connect is by far the best file sharing app there is. The stuff you need is always there (movies, adobe software, mp3s, music videos, p0rn) and its reasonably fast(10-100K/s depending on the user).
I also have KaZaA, but that thing has very few files compared to DC. I can't even find ONE movie on it.
of course, napster, imesh and gnutella suck (we'll have to see how the new gnutella protocol does)