For me it depends on what I'm lookin for. For dark guitar samples I'd turn to folk music. For that "laid back but still gansta" vibe, Jazz (60s/70's). Clever vocal phrase (blaxploitation flx/ old movies). Foriegners got some heat too (Arabic music, old latin pop). Emotional tracks (R&B/ Soulful gospel/blues).
What I don't typically sample is country (you can have it homes). I sample classical stuff..... but not from classical music. For strings and that classical vibe I grab movie soundtracks/scores, or symphonic jazz.
Me and my synth didn't always get along, but since my needle died we've been getting to kno each other better.
Production Set Up: Akai S900, S1000HD & MPC2000 (w/18megs, EB16 FX, CD-ROM, and Zip Drive) - Korg MS2000BR - Roland JV1080 (w/Vintage and Dance exp. cards) - XV5050, XP10 & VS880EX - Groove Tubes GT55 - Sony MDR7506 - Technics SL-D202 - Deep Crates-