Sigma 10-20mm f4-5.6 DC HSM. For Canon D-SLR.
This was my favourite lens until I upgraded my camera and can no longer use it.
Beautifully sharp wide angle images! Fits most crop frame Canon SLRs.... Incredible lens!
£250.

Details and photos here:
http://www.amazon.co.uk/Sigma-10-20-f4-5-6-Cameras-mount/dp/B0014RDRHG