I've been working with more rappers lately and can consider myself to have somewhat of a clue.
Personally I'd go for the Digi02 if you are only doing rap. You don't need as many simultaneous inputs and personally it sounds better and is built better than the Roland. The sliders on that Roland look like they'd last about 2 of my average sessions.
The Blue Kiwi microphone is overkill for rap and hip hop. A lot of rappers I know like either the Rode NT1 or Shure SM7. Get a decent outboard preamp though (Focusrite Penta is okay for the money, if you have a big budget and are serious about your pre look into something like
the Manley Voxbox or even a ISA series Focusrite). A smaller studio around here that does rap uses Studio Projects B1's and C1's and they sound fine.
The Triton is an okay choice... I guess. I never was too impressed myself with its sounds. Everyone and their brother has one too. If you're insterested in pro sound look into a Kurzweil.
The Akai MPC is good for rap, but why not save some money and get the 2000?
For rap I'd *seriously* look into getting a real Roland 808, or a TBS Syncussion, or even
a Novation DrumStation to use as a sound module. The 808 will require a MIDI retrofit to use with whatever sequencer you set up. Another good dedicated piece of gear is
the Studio Electronics SE-1. This is the deep bass you hear on a lot of big budget R&B, hip hop and rap albums these days (basically it is a rackmounted Minimoog).
Honestly, look into a program called ReCycle--which is specifically for sampling/looping and beat making. Easy to use and effective for hip hop/rap.
Hope this helps.