I would go for the Mac Pro if I was you for sure.
I would consider myself to use the computer in a similar way as you are.
I purchased the top of the line MacBook Pro from the online

store and had it less than 2 weeks and returned it.
It runs too hot to be on your lap, the screen easily warps, i would close the lid and it looks like it was smiling at you. Mine may have had some extra issues than most but the keyboard was less than responsive, and the trackpad had random issues.
I will be ordering a Mac Pro by Friday of this week.
8gb ram from Newegg.com 4x 2gb
and this from the online

store
Specifications
* Two 2.8GHz Quad-Core Intel Xeon (8-core)
* 2GB (2 x 1GB)
* 500GB 7200-rpm Serial ATA 3Gb/s
* 500GB 7200-rpm Serial ATA 3Gb/s
* NVIDIA GeForce 8800 GT 512MB (Two dual-link DVI)
* One 16x SuperDrive
* AirPort Extreme card (Wi-Fi)
* Apple wireless Mighty Mouse
* Apple Keyboard (English) + User's Guide
Subtotal from Apple $3,024.00
Subtotal from Newegg $339.98
Total (no tax added) $3,363.98