Okay I can help a little bit, most if not all mainstream hiphop is compressed MORE THAN ONCE.
Make sure the beat your spitting over is tracked out, not just an mp3 with a beat on it, surefire way to get crap....Another surefire way to get crap is to record/mix in an untreated room. Read up on acoustics hint OC703.
ALMOST always use a compressor during tracking for hip hop, and be a little more liberal with it than most genre's. But still only light compression on the way in. No more than 7 db gain reduction tracking, just a rule of thumb.
Than compress again in the mix.
if your mastering yourself throw a limiter on at the end, maybe even a lil compression on the master fader depending on what comp's your using.
You want a compressor thats fast for rap, because rap is aggressive, fast compressors tend to not have the "color", "thickness", "Depth" of their slightly slower usually tube driven counterparts.
Classic hip hop vocal set up, Mic---Preamp----UA1176 used for compression during tracking, than something warmer and fatter like the LA2A for compression in the mix. ONLY COMPRESS LIGHTLY ON THE WAY IN.
Mic- Check out the forum favorites, I use a Rode K2, great for the pricepoint and has variable polar patterns, is a tube mic
(I say for hip hop get all the warmth you can before it gets cloudy, starting at the mic, plus Omni Picks up incredible depth on vocals with no proximity effect which allows the rapper to be more dynamic around the stand, but if your room isn't treated VERY WELL, you will hear every fault in your studio loud and clear, than go to cardioid. (The majority of vocal mic's are Cardioid).
Ive used an AT4047, it was a very nice mic as well, a little cleaner but less character, could be much better for alot, in fact most uses. (accurate representation is what to aim for, than from there aim for what works best on your voice or for the beat your on.
The AT5050 Im sure is great as well, they make solid mics for the pricepoint, just make sure its suited for you...I can't remember but I think the 5050 is a tube mic, which will add more character.
SURE SM7B, A favorite of rappers and home recordists everywhere always. Really picks up the low end/bass in your voice, sounds great on aggressive shit, pretty sure wu-tang used one, if your on a budget this is your girl. A measly 350.....ADDED BONUS, THIS MIC HIDES YOUR ROOMS PROBLEMS LIKE NO OTHER, you may literally save a thousand dollars on accoustic treatment by choosing this mic. (accoustic treatment is EXPENSIVE and HARD WORK)...I should mention I am looking at picking one up, most my buddies sound better on the SM7B than the K2 (at double the price)...plus my room has issues, still..... no lie.
If your rich check out the U87, the Peluso 22 4? LE, the Sony C-800.....and anything else you see is expensive and read is good.
You need a good preamp, not the one on your interface,
the GAP PRE 73 is all the rage in the world right now, its an 1176 "Clone" thats upgradable...they have shootouts against the 1176, its not bad.
Groove Tube Brick - Very solid preamp, Cheap, another tube product...more warmth...great DI incase your into beats
BLA Auteur- Thats the one I picked, Great depth on the low ends and a nice crystally but not sibilant sheen on the high end. (Some of the high end may be slightly lost IME, just my ears, works great for my voice which is slightly more nasally than I would choose.)
Converter The Behringer one works fine, The BLA converter/clock that can go with the auteur looks pretty cool though.
If you can go to a hybrid studio where you bounce to tape and back at somepoint.... I've found that a decent improvement as well.
Automate vocals, don't leave them at the same volume through the whole take. FADER RIDE IT.
Ok, thats good enough for now...Had to explain the current sound of rap (other than in the sense of drums, keys) etc.... isentence I would say the character of the tracks are (Overcompression, Analog(esque) at least, Tube equipment)
Its a shame everyone does it like that because it's so easy to replicate, than we see talentless fools sounding damn similar to Icons, but its great on the other hand cuz we all can be heard now. Double edge sword bro.