I like to create my own drum loops based on single shot samples (non-built-in Fruity Loops samples). So to create the drum loop, it's a combination of individual percussion sounds. I just prefer it that way because I can make the loop the way I want it and edit the individual sounds such as putting a bit more reverb on the snare, but messing with pre-made sampled loops ain't bad sometimes, you can get some nice results sometimes or oldschool grimey feel or something.
Sometimes I also like to synthesize my kicks and other percussion sounds. For example, an 808 sounding kick, I sometimes synthesize that myself rather than using a sample. Sometimes also with other wierd percussion sounds like zaps and blips or something of that nature. I don't like to emulate anything that sounds better in it's acoustic form, like a snare. I guess it depends on your style as well, if you wanna sound all techno-ish with your percussion, then so be it, that's not my personal style for HipHop beats.
Also anything that's "synth" based such as synth basslines, leads, pads, etc... I will synthesize those rather than using samples. It sounds a lot more natural. Using a synth FX noise is a different story though, I might use a sample in that case, but with anything that has a melody to it, then no.
As I said about the snare, I don't like to or atleast prefer not to emulate anything that sounds better in it's acoustic form.