09-18-2009, 05:12 PM
The Mac Pro is going to be the most powerful of the Mac's available (and also crazy expensive) as compared to the others. It does have the beefier processor, lots of RAM and with it's standard case, allows you to upgrade very easily.
The iMac is the next in line and has a good processor and enough RAM as well and is cheaper. Upgrading this is a little bit tougher, but can definitely be done. The advantage here is that you get a nice monitor and takes up little space.
the MBP is of course the laptop and way cheaper (compared to iMac/Mac Pro) and can definitely be used for development.
The one you are missing/ignoring is the Mac Mini, and at a starting price of $799 is the cheapest of the Mac's. I currently use one for my iPhone App development. Since I already have PC (and keyboard, mouse, monitor), I just used a IOGear KVM and hooked up the Mac Mini and it's been working great.
The Mac Mini is the toughest to upgrade, but if you do upgrade the memory to it's max allowed, it actually performs quite well..
If you're thinking about using the Mac as a long term thing beyond your dissertation, then definitely look at the beefier machines, but don't ignore the Mac Mini which can hold it's own..