Is the xp30 a good synth for hip hop music and r n b. Will it work good with an mpc2000 or is it better with cubase. Or should I look
for something else???

If you are using a computer the XP-30 is good, before you buy check out the drum sounds because rolands tend to have good sounds but not that good drum sets. Other option would be the korg trinity which is more expensive and you get stuff that you wont use if you are using a computer. Check them out.

If you're going to get an XP-30, you might think about investing a bit more $$ for the Hip Hop expansion board along with your purchase. Though I don't own this board myself, I hear it's excellent.
Without that expansion board (and maybe even with it), you'll most definitely need a dedicated drum machine or sampler because the XP's drums really suck shit and you can't sample your own stuff with this thing either.
Other than that, it sounds great and with 1,000+ patches built in, would probably work well for almost anything.