I think Hip-Hop heads shouldn't be scared to try new things, it's not written in stone that if your a Hip-Hop producer YOU MUST SAMPLE VINYL ONLY. My opinion is sampling is sampling ill regardless of the medium used to sample from, your not any less honorable if you don't sample from vinyl and any low end effects or sound qualities your looking for famous in vinyl records can be reproduced to some extent especially at the mixing and mastering stages of completing of a track. And then you may not always want your tracks to sound like a vinyl record at least for me it doesn't cross my mind to do that, my only thing is getting good sounding shit period! If you do sample from MP3's it should not be CD Quality but better because remember it's an MP3 so an MP3 at CD Quality isn't really CD quality and then once you convert the MP3 to wav or Aiff whatever format your working with, spend some time in Soundforge or some other audio editor and bring out those frequencies that may have been lost during compression if you can. Just be true to yourself and your music and do your thing, technology is here to stay so may as well use it to your advantage!