I also use a 17" Macbook Pro
Processing power is not an issue (2.6ghz Core Duo/ 4gbDDR)
I have the glossy, high res, LED backlit screen and I
LOVE it! It's as good as any LCD for photography.
Negatives...
- Portability...it really isn't THAT convenient to carry (but better than my previous 17" Dell). For portability I'd probably look to the 13" or 15"
- LCD Monitor...yes I love it, but LCD screens really aren't the best for image editing...even the newest LED Backlit ones.
- Cost
My
ideal setup would probably be the 13" Pro with glossy LED/LCD AND a monster "desktop". I actually think you could get a good Mac desktop with similar specs + 13" Macbook for not a lot more than My 17"