Aww come come now, we've yet to mention the program with the largest file share (by 4x), the best for ISO's and movies (although very much not for mp3's), and the most reliable.
Direct Connect . Takes a little bit of brains to get working (if you are on a firewalled system you have to use passive to be able to search), and if you want to get on the better hubs you can't be just a leech, but you can find anything anyone is interested in. Has slots, meaning you will usually get good transfers from people with good upload speeds. Less "renamed software", and you are able to browse peoples software lists (so, go up, get a guy with a T1, and find something good to download).
It has its downs, for the most part you can only access the user-base in segments, which makes for faster surfing but a split group. People, as with all F/S progs, can lie about their connection speed, and rename one thing to another (always always check yer filesizes with the release, never try to get a homemade unless you are desperate). D/C is still the best option however, for Movies/ISOs.
As always I reccommend not getting so enamored with one prog that you dump the others - combine them and get the most.