these statements are getting ridiculous; i doubt any of you have actually used a 17". i have (for a couple of weeks when my 15" was dead) and the difference is noticeable, but not problematic. the footprint of a 17 vs. a 15 is about 1.3" wider and 0.8" deeper. you are telling me that the extra 1.3" and 0.8" makes the laptop not fit on small tables? please.
is it heavier? yes. is it bigger? yes. is it "not portable?" no. i went to the 15 for 2 reasons: 90% was i would be using it primarily at home on a big external monitor and the size difference would not have really been a benefit for me; and 10% was that i had a hard time finding a bag for a 17 that did what i wanted it to do.