You could do alright for around $5K.
Just a suggestion, I might try doing some research on each specific area you're looking to address, go to the store/dealer and try out some different options. No one here can tell you exactly what you should get, because we don't know what your priorities are, what you're going to prefer working with, and what's going to sound good to your ear and personal taste.
Since you're at the mic forum, I could make a few suggestions in that department:
Since you're going to be doing mostly rap / R&B, I don't suppose you'll be needing a lot of instrument mics. Do you plan on tracking real instruments, or will you be doing all synths, electronic drums, sampling, etc?
Even if that's the case, you might still want to have a few instrument mics around for micing guitar and whatnot.
My guess is that you could get a lot of things done with a couple of quality condensers . . . something along the lines of the all-purpose type, like the shure ksm32. There isn't much you couldn't handle with a couple of those -- even on the rare occasion that you might mic a real drum kit.
You should also have a few sm57's around . . . just because you should.
The most important thing for you, obviously, would be to have a good selection of vocal mics. For that, I'd recommend going to the store and trying a bunch out. Look for ones that sound good, and look for ones that sound different from one another. I say different because different mics will sound better on different voices.
Then, before you actually pull the trigger and buy them, come here and tell us what your final candidates are. Just run it by us quick, and if any of them suck, we'll be sure to let you know and warn you.
As long as we give you the green light, then go and run with it.
As far as sound cards go, you might want to pay a visit to the computer recording forum just down a ways. For mic pres, there's a rack forum just below this one, and there's more of an all-puprose one just below that.
