Question is simple: what would you purchase thinking about photo editing (Aperture 2 and CS3 should run at the same time) and other regular apps. The available budget is around $3000.
Szimi
Well I recently purchased a new MBP desktop replacement machine and take it with me on trips (best of both worlds). The ultimate aim is to purchase a 23/24 or 30" LCD for editing at home on the MBP. I've set up a mini docking station using a notebook stand, and USB hub (external keyboard, mouse and time machine backup drive) so when I get home I can just plug the single USB connector in and power and use all the external components.
I've upgraded to 4GB RAM (custom - don't buy apples, far too expensive) and it runs Photoshop CS3 perfectly, usually I have a numerous applications (including vmware fusion) open and don't notice any degradation in performance.
But if you don't anticipate ever needing to travel with the machine or you already have a laptop, the iMac may be the way to go, I have no experience with these yet (getting one later in the year for the other half).