What would be the proposed benefit of sampling from 8 track, other than the novelty of it?
Sampling the Audio out from a DVD player will greatly expand your sampleling horizons. Keep and eye out for obscure DVD titles in the dollar bin at Wal Mart.
Don't be afraid or feel bad about sampling from CD's. The fact of the matter is that, "digitally remasterd recordings" have done all the work for you! Whereas you would've sampled from vinyl and process it the same way the professionals who re-relase original recordings to CD do. You'll soon find that "record dirt" 9/10 times will end up getting lost in your mix anyway.
Don't get caught up in the hype that you have to sample from vinyl. Sure it's cool and you feel like your paying your dues to the art as a "hip hop" producer, but the fact of the matter is that effeciency plays a great part in the creative process of finding that next hot sound.
Yes, CDJ's are a blessing!