I sample from any source i can get the drums from.CD,Tape,Radio etc. and some samples are too clean. so i will not hesitate to use vinyl to dirt it up. I own alot of classic breakbeats on cd and thats great,but some songs i get drums from come from cd only, no record presses or tape. I'm always listening for drums even when i listen to the radio at work, also check wikipedia for gathering info on what samples were used in your favorite classic hip hop songs. i'm a sound editor who makes custom libraries for my fellow producers.I also build computers for my fellow producers who are new to computers and can't afford outboard gear.I believe having your own custom library will give you a different sound than alot of "Cookie-Cutter" producers.Have a distinct sound,it will make everyone know who did that beat!