17" big?? YES too big??? you have to decide for yourself...
one of my clients has a 17" now... its a desktopreplacement... but he told me if he would have to do it over he would go for a 15" or even a 12" to make it more portable and then get a 20" apple display + kb/mouse to dock it on his desk...
but if you're an american: go and buy the 17"... because 80% of all people in favor of the 17" live in the us I guess

here in belgium I remember going to the apple seller... seeing the new line up 12/15/17 and instantly falling for the 12" wich my brother then bought...
the store manager told me he sold a lot of 12" to students, 15" for people who need to do a lot of work on it... and the 17" only to people who want it big, probably didn't even need it & didn't care about price & size... & in most cases popped it in the back of their Mercedes ML/BMW X5/... and drove off

hahahaha
I saw a similar case now when I was there with the 30" Apple Display... I would like it because it has the same total res as my 2screen setup I use now... but I can't afford to buy something that big

but I saw a woman with a little doggy... and she needed a new computer.... so she bought the 2x2,5 G5 (no 2,3 or 2,7 at the time yet) with 2GB ram (because you need some more she told the vendor) and the 30" because that would be nice to watch DVD's.... she was lucky they had both in stock... so they popped it in the back of her Porshe Cayenne Turbo... and off she went...
I could have hit her... a lot of people I know would like that kind of setup to work 24/7 on it... and she buys one... to surf the web & watch dvd's :s
damn...