I've never used a sample that I haven't synthesized myself because I feel as though I wouldn't have proper control over the sound. Then again, I use Reason, so I can't be arsed to load a bunch of samples into the NN-XT, process, export, re-load, boring...I also don't use a lot of FX, I use effects on aux sends.
Someone mentioned FM - that's the ticket for chimey sounds.
A shuddering sound - I'd love to be able to make. I would automate the filter cutoff, LFO amount&rate to cutoff, pitch, LFO amount&rate to pitch. It seems to me that it's really about having control over the rate and depth of the LFOs to get the movement desired. Using noise is a great idea.