Honestly, if I were starting fresh without any peripherals and wanted the best bang for the buck then I would get a cMP 5,1. Like the one I bought for my wife recently. Lots of "power" and the ability to upgrade the GPU and such without much fuss.
Since I have a TB display and TB RAID for my own setup that limits me on what I can do, so I'm waiting to see what happens with the Mac Pro. My current nMP is fine for what I do, my only complaint is with the GPUs and only having TB2 means adding an external GPU isn't going to give the best performance, plus I'd need a new display.
A MacBook Pro for "power" is great on paper, in use it's not that great once the fans kick on high so it sounds like a jet engine and you end up with thermal throttling.
I have one of everything except for an iMac in this house; Mac Mini, MacBook Pro, cMP, nMP. I use my nMP the most, wife uses the cMP, and the MacBook Pro doesn't get much use unless I decide to work outside of my office.