i have two distortion/overdrive pedals (not countin my zoom something-or-other with lots of little things to muck with):
boss metal zone, which is very hard sounding, and requires a bit of tweaking to get the tone just right (i typically use it with my musicmaster amp with my cheapie
alesis microeq-gives two stages of para eq on the mids, and full para eq on the spectrum. this usually does the trick.
marshall guv'nor, from before they discontinued them some time ago (i believe they brought them back)-damned thing is night indestructible. not especially a standout in general, in my opinion, but pair it with a fender, and it sounds SWEET! like magically turning a bassman head into a JCM800, at least at first listen. it is great for that application, not sure about many others.
i don't think i'm going to be looking for another distortion anytime soon, unless i learn to build my own, because i prefer the regular distortion in a 2-or-more gain stage amp typically. there's something very organic about it. of course, it helps to have channel switching so as to have at least a couple of options, but for recording, it doesn't really matter.