Sigma 17-50mm f/2.8 EX DC HSM Auto Focus Wide Angle Zoom Lens is $399 at Adorama.

Plus you get the 4% reward. This came in an email as a 4th of July sale, so it may be just today, I could not find anything on how long it is at this price. I thought I got a good price a few months ago at $20 higher.

[stein]

I'd say it's a fair price (currently same price listed at B&H and on Amazon as well), paid approximately the same a few months ago, but in Euros (360€) which was a good deal while the next best price was closer to 386€ which would roughly translate to USD430. I was a bit ticked off at the time as the same lens for Canon was listed 100€ cheaper (286€/USD318) but once I started using it and saw the results, the state of frustration was immediately replaced with bliss and pleasure