Looking to get my first MacBook PRO and cant decide between 15" and 17" models. I like the higher resolution of the 17" but am concerned that it will be more awkward and heavy to bring around with me. Can anyone who has had both let me know if this is the case or is it barely noticable? Do the extra features of the 17" make its extra bulk workthwhile? I travel a bit (once a month through airports) so this is an important factor for me.