I have never really used samples made by other people, other than when first messing around with a tracker in 2000 or so, which was the first time I had made music on the computer. Even then, I started very very quickly synthesizing my own sounds with Absynth (which by the way was a pretty crappy experience, I found the program really arcane or something).
These days I produce full songs in Logic and have not touched trackers in about 7 years, until just last week when I found MilkyTracker and realized trackers are a lot cooler than I thought, years ago.
Regardless, even now, if I keep working in MilkyTracker (as a side project, since I require a full DAW+hardware studio for my band), I will be synthesizing my own samples with my hardware synths. I've got a pretty diverse set of synths that can create some very very nice sounds, and frankly I wouldn't feel good about using sounds someone else made. For me, what's the point in doing some creative artistic work, if I'm working off someone else's product? I can understand using some samples of, some 303 squelch, or something, but even then, I will make that myself anyways, and give it my own unique touch, with some extra modulation or who knows what.
That said, I also set extremely high standards for myself , and how I go about doing things, so this probably isn't that common of a perspective in the tracking scene... I don't know, though. I've never had even the slightest involvement in "the scene", until the last week or so.
The only samples I still use today are a small handful of nice simple drum sounds, which I actually re-shape and modify very excessively to fit my tastes.