Most people have certain sites they go to to get certain things. I, for example use oink for music, bitme for elearning, myspleen for animated tv shows, empornium for porn, etc etc etc.
Similarly, I'm betting most people have a default site where they go to get everything. so what's yours?
I'll start off...
My favorite "everything" site is demonoid. Why? it's got a ton of files, consistently good (but not GREAT) speeds, an effective searching function, a good selection of mac stuff, and even the option for external torrents.
It seems as though every time I use torrentspy or isohunt to track down some random torrent, it just ends up spitting out a link to a torrent already tracked on demonoid.
Lastly, since ratios are only loosely enforced, users generally don't have the fear of downloading that is common in some invite-only sites (oink?). That way, there's always leechers, in case you actually want to improve your ratio.