Mostly those single-note single-instrument samples and drum samples. It's a personal thing for me, as I like having more control over the composition of the song. Multiple-instrument single-note gets iffy with me, but when you have chords and arpeggios, I just guess I can't stand it unless I sampled it myself. Same with drum loops.
Yah, I agree with the jazzy part. I really love jazz, but actually achieving a jazzy sound is pretty hard for me, as I didn't discover jazz until fairly late, when I already had a classical repetoire.