Well, I just made the migration, too. Bought a Mac Pro and added 4 gig of RAM from Newegg. The Newegg works just fine as far as I can tell.
For what it is worth, I have encountered two problems configuring my Mac Pro for my photo work. I use Qimage and an Epson R2400. I installed Parallels and Windows XP so I could continue to print with that combination. Big mistake. It is nearly impossible to get Parallels to print to an R2400. There are a zillion posts on this subject, mainly from frustrated folks who have tried and failed. I found one workaround that works, more or less, but it took me three days of my life trying a lot of other ways that failed. In the end, someone suggested that I try Fusion, so I downloaded the trial version, and it worked like a charm. No problem installing the printer and Qimage.
The second problem I encountered is getting my Nikon 4000 ED scanner to work with my Mac Pro using Silverfast. I downloaded the latest version of Silverfast and found that the program freezes every time I eject a film strip. Bummer. Same thing with Nikon Scan. I've tried a lot of fixes for this, starting with uninstalling and re-installing the software, but so far nothing has worked. I spent the better part of an hour on the phone tonight with Apple support. The technician said that this has not been reported as an issue by others. He checked the operating system, the hardware, etc. and concluded that it is not caused by a problem with the computer or operating system. I've contacted Silverfast support about it and am waiting to see if they have an answer. In the meantime, Vuescan does work, so I can use it if need be.
Other than that, my Mac Pro migration has been pretty easy. It's a great machine. Hope you enjoy yours.