I always carry my bag around with me when I'm shooting so it makes no difference. I need to carry an extra battery and card with me all the time, and honestly usually don't even notice the weight of an extra two lenses on my back.
If I were just carrying my camera around all the time I'd definitely agree with you, though.

I didn't even know that existed! Thanks for the heads up, for that little money I might buy one for next semester and trade in my 18-55. VR makes a big difference... still no substitute for a faster lens, but it helps.

My friend's dad shoots with the Sigma 18-200 and its SUPER crisp, and somewhat less expensive than the Nikon Lense. I know the aperture isn't quite as large at max focal length, but it may be something to deal if you are looking to cut cost. he uses it to shoot weddings and his pictures are absolutely gorgeous. I am actually thinking about picking one up myself, after I get my new printer and possibly another body.

If you do alot of sports, you may want to look at a 70-200 2.8 AF-S VR. It is a bit pricey, but it focuses lightning fast and the VR can help with hand holding shots at slower shutter speeds.

plus it has a constant max aperture of 2.8, which is needed for low light when shooting sports photography.

just remember that VR doesn't have any effect on eliminating motion blur; VR is only for hand/camera shake. The only way to get rid of motion blur is a fast shutter speed, generally 1/250 or faster for sports photography.

it also has a lower apature at 70mm then the 18-55 does at 55mm