I agree that the 17 inch MBP is just fine for travelling. True road warriors might want to consider something a little smaller and lighter but for those of us who don't have to carry a laptop around all day every day the 17 inch MBP is a great machine. My 17 inch MBP, and its predecessor, a 17 inch Powerbook G4, which was the same size and weight as the MBP, have travelled all over the country with me for more than seven years. Better yet, it has been years since I regularly used a desktop.You've got to think the MBP 17" is absolutely feathery compared to that beast.
Please...please don't pay much heed to anyone who tells you the 17" isn't portable. Guys like you and I who have carried massive brick laptops understand what it means to not be portable. The 17" is tiny in comparison, especially being as powerful as it is. It's more than portable.