I like the AKG 414, It works really well for what you are doing.. A friend of mine( which i currently built him a studio) uses the 414 and it sounds great in that application

Personally I think your choice of the Rode or Sm7 would be better for rap. But if I had the choice, I would hunt down either an NTK or an RE20. Just personal preferrence though. I'm sure someone else will have a very different opinion.

Male or female voice?

Male..

RODE NT2
RE20

hmm oke..
and which Preamp?

and i read lot of the SM7B.. mic. is good for hiphop/rock..

in the price range:

Groove Tubes The Brick

Universal Audio SOLO/110

for a bit more:

Great River ME-1NV

I have the UA solo 610 and a Summit 2BA-221, they are both very good but do things differently. The 610 is definitely the better for tone, the Summit has a few more bells and whistles and is more flexible for different Mic's.

The Summit unit is a little less colored unit than the Solo 610 and seems to me to have more highs. I have not test them as much as I want to though. The Summit also seems to distort a little faster with low frequencies, like I said more high frequency friendly.

I also have the Great River unit and it is a fat warm almost tube sounding unit that really shines with bass freqs and has a warm mellow sound overall. But it is colored.

Those preamps are great for anything but the great river is $1000+. The summit about $600+ and Solo 610 can be had used, since it has tubes I wouldn't buy a used one unless you know about tubes.

So I would think about a Grace 101 or RNP. Use the rest of the money for the best mic you can afford like an RE 20 or AKG 414, Rode NT2. A clean noise free signal is more important than color IMO for your type of music.

I'll guess and say you are using a PC to record with so I'm sure they have some type of modeling to add some warmth and compression to the sound if needed.

Get the cleanest possible sound with the least amount of noise first. I do a different type of music and clean is not a priority, big fat tone is.

hmm .. and how is the Neumann TLM 103 for rap ?
example with the RNP or Focusrite Trackmaster Pro ?

I always thought it was more what vocalist you are recording then the genre of the music when it comes to microphones.

That's why I would get something that's versatile if you can only have one. Whatever you choose do yourself a favor and if you don't have a Shure Sm57 or 58 get one.

+1 - 57/58, preferrably both!