I would say this is easy to answer yourself - it depends what you use it for and how frequently you travel and whether you can afford it.
If you need a machine with lots of power, especially for CAD or graphics or photos, then 17". You will appreciate the screen size (especially high res). If its just for average use then 15" will meet your needs. They are about the same weight, the 17" size is getting to be a little awkward, but then the 15" cant be dropped into a pocket either. The cost - only you know if you can afford it.
I bought a 15" MBP for the mobility but in the end I found I travel so much and am away so much that its too small now - I need a desktop replacement and a high res 17" screen for muscle and graphics work (and DVD's). I got tired of waiting for a small powerful laptop from apple so I just got a 2nd hand 12" 1.5Ghz powerbook for short trips, holidays, email, light use.
I guess the 15" for me was neither big enough or small enough, meeting neither requirement.
If you need a machine with lots of power, especially for CAD or graphics or photos, then 17". You will appreciate the screen size (especially high res). If its just for average use then 15" will meet your needs. They are about the same weight, the 17" size is getting to be a little awkward, but then the 15" cant be dropped into a pocket either. The cost - only you know if you can afford it.
I bought a 15" MBP for the mobility but in the end I found I travel so much and am away so much that its too small now - I need a desktop replacement and a high res 17" screen for muscle and graphics work (and DVD's). I got tired of waiting for a small powerful laptop from apple so I just got a 2nd hand 12" 1.5Ghz powerbook for short trips, holidays, email, light use.
I guess the 15" for me was neither big enough or small enough, meeting neither requirement.