Once had 1900*1200 (or something near that) on my 15" Dell and it was great - not tiny for me all all. In fact, I liked it so much it stopped me going to a MBP for ages until it was rudely stolen a year ago.
In the end a got a 15" MBP and actually the lower res isn't so bad:
1) Mac apps take up less vertical screen real estate in general.
2) Good use of Spaces and Expose mean that you have all the pixels you need.
3) Everything is very clear.
The only time I miss that res is when I'm either designing very large wireframes or working on very large project plans. Which is rare.
In the end a got a 15" MBP and actually the lower res isn't so bad:
1) Mac apps take up less vertical screen real estate in general.
2) Good use of Spaces and Expose mean that you have all the pixels you need.
3) Everything is very clear.
The only time I miss that res is when I'm either designing very large wireframes or working on very large project plans. Which is rare.