you're not going to find a smaller, lighter 17" laptop. if you're not going to be carrying it everywhere you go, i think it's a fine decision. you've got more pixels and screen real estate in your laptop than i do on my 20" cinema display. so don't fuss about your purchase; you and millions like you should be happy.
that is, unless you do take your laptop with you everywhere you go, lugging it around, trying to find comfortable space for you to work. do you really want to be burdened by all that weight, especially when everyone around you has got smaller and lighter laptops? the sight of a less than 3 lb laptop would make yours feel like a brick! sorry, bub, wrong choice. but of course i'm just kidding! congrats on the purchase.