Sold my D60, 18-200, and SB400 flash to an interested buyer. Bought a D300. Wow! What a comfortable camera.

Currently short on zooms now. My 18-200 filled a lot of holes.

Can't afford the Nikor stuff right now so was wondering if anyone had any experience with the

Sigma 24-70 2.8

and

Sigma 70-200 2.8 APO HSM

or any other opinions on third party lenses that fit the 24-70 70-200 2.8 format.

Specifically, I'm looking for performance feedback at wide apertures for portraiture.

Thanks