Being a regular on the KVR Audio site, I'm not sure it's the place to go looking for soundfonts. Most folks there are using softsynths, but not in a general midi sense of things. Very few 'orchestral' composers there. Mostly electronic stuff, some rock, less folk and very few folks using GM as a backing track mindset.

I'm trying to remember the old sites that were the treasure trove of soundfonts and I'm drawing a bit of a blank. Soundfonts.it used to be one of them, but Guido has moved on to much more interesting stuff with physically modeled instruments that are actually outstanding.

Ah yes, google is our friend. Hammersound.net is a huge one: http://www.hammersound.net/