My glass list includes now:

Sigma 10-20
Sigma 24-70 2.8
Nikkor 50mm 1.8
Nikkor 70-300 VR

Not the "best/most professional" glass available, but with what I shoot, I cant really tell the difference between the Nikon equivalent (for instance the 24-70 2.8 Nikkor) that costs almost 3x as much. I know its in the glass but it IS in the body too. Like Chris M said, you dont want a slow camera, and I was getting ahead of the D50 by quite a bit, and since I may be shooting for my school paper now and then, having this will be awesome at a few football games and I'll borrow their 80-200 2.8