Hi
Starting a project studio eh...nice
Let's see if I can give you some helpful infos.
Well, first of all the DAW: if you mostly sequence and need great flexibility at that I'd say go with Logic: the learning curve may be a bit steeper, but for MIDI and arranging tasks I think it's the most comprehensive; plus, if you work on the Mac platform its integration with the G4 or G5 is solid.
If you can, try to go with a Dual Processor, rather than a single one, or save up and get a G5 (IMO a dual G4 will be more than enough and with all of Logic features like freeze DSP shouldn't be a huge problem, but I don't know your DSP requirements so you might want to read some reviews and on top of that I'm not a Mac user so I may as well shut up on thistutt ).
For an audio interface the 002R from Digidesign is certainly a good and complete package, that would provide you the ability to run Pro Tools for recording/mixing/audio editing tasks (better and faster than Logic at that IMO) and Logic for all the MIDI work, be sure that the Digidesign Direct I/O driver works well with that combination.
If you decide for another soundcard the RME are certainly great quality (audiowise), though MOTU offers more complete solutions (kind of like the 002R from Digi), that include monitor sections and analog+digital I/Os.
Monitors are a very subjective thing, for example lots of people like and swear by Mackie HR824s, I can't stand them and like Genelecs ( I have 1030As); I haven't listened to the 624, but I guess that being the 824's little sisters they should be very accurate in the high end ( the 824 sound painfully bright to me).
I suggest you try out a few pairs like the 624 or Event (which have some good models at reasonable prices) with a CD you know very well IN YOUR ROOM and decide what you like best: try to pay attention to an even response without holes or werid bumps, and listen to the midrange which I think it's the most important part for a speaker.
I guess mics and preamps/toys will come down later right?
An often overlooked factor in project studios is the room treatment: no recording or mix will sound good in an untreated room as there's a tight relationship with your speakers and the room you use them in, so you may want to save a little for some room tuning, even if minimal, some HF controlling and bass trapping will make your room not perfect but usable at least.
Hope this helps
L.G.