It's working okay for me...
I also do a lot of photo editing and publication work, but it's a second job that I do whenever the business comes my way. So given that...
I held out for a Santa Rosa MB (midline white). I wanted to 2.2 newer C2D processor, the 800mhz bus and the new, faster, better Intel X3100 integrated graphics. I have 4GB of RAM and a 200GB 7200 Hitachi HD, so my MB is a little souped up. But I can tell you that after using an older model MacBook (midline white 2.0 C2D) and immediately switching to this has been a big improvement. Rendering is fast, resolution is crisp, and all of the tools and filters run faster and are quicker to respond/process before. I noticed that on MacWorld, they'd benchmarked the new SRMBs and the midline one and te Black one actually out perform the entry-level MBP on a few tests. It can't compare to a dedicated graphics card (even the entry 128MB Nvidia is way better), but if you are used to integrated graphics on your laptop, the SRMBs are a VERY nice step up.
And don't slam me on this, but if you do boot camp, it will use anywhere from 128MB to 384MB of system RAM. I have to keep a Windows machine of some kind to do some different stuff for other folks an I have noticed a big difference in Vista (which I hate, but I have to use it). That is what the specs for the chipset state from intel's site. For some reason, the drivers that Mac provides don't allow that kind of access. Not sure why they stop at 144mb...
I think it just depends on how much real estate you want. I was ALMOST going to splurge and get an entry MBP, but the MB is so much more affordable and upgradeable, I just wanted to stick with it. Plus, the 3yr AppleCare warranty is significantly cheaper for the MB as opposed to the MBP. I agree with what the folks said above: you can get a great extension LCD and a new SRMB at 2.2 C2D for less than the $500+ for a MBP entry 2.2C2D. I have been running mine via DVI dongle to a really nice Dell 24" flat screen at work, and it has been amazing (especially compared to the older graphics set) so far.
If they really go with what a bunch of folks are talking about concerning the much-anticipated and hoped-for MBP revamp that has some of the super-cool features from the MB like a removable HD bay, the flat-keys keyboard (and backlit!), higher 15.4" resolution, eSATA port, new magnet closure latch, entry-level model at 2.4 C2D.... I would be incredibly tempted to sell this to get one.