I've searched for drum sounds for a while, and the raw wav files are out there, you have to dig for them. I use the search bar @ KVR a lot. There's a Hawaiian music studio website (can't remember name) that's got some killer Yamaha drum samples, but you have to load them into a sample player. Huge download; took me hours to get them all. There's mapping for sfz, but I didn't bother with that. My sfz player (Plogue Aria) is a little wonky. It eats up a lot of my proc speed, so I record the output to a track and save the horsepower for mixdowns.
Drumcore Free has Gary Thompson's Ludwig kit, a bunch of MIDI files, and some percussion sounds (congas, bongos, maracas etc). Can't add files (MIDI or wav) to it, but you can use it to play back sounds. Pretty fat sounding, sort of 90's attitude. Easy for demos.