i cant wait for the 70-200 EX DG OS HSM OMG BBQ!
well, if it has a lot of letters its better right? 
anyways, never tried any other company before other than canon for lenses but the OEM products are expensive as it is so i want to branch out. but the lenses i want thats 3rd party are either more than the OEM counterpart or they dont have what i want. so since sigma announced this, then im looking forward to it!
i was looking for a 70-200 with constant aperture of 2.8 but the canon 70-200 2.8 IS mark 1 would still cost an arm and a leg even if bought used....and i for one TRY to stay away from used unless i can get a considerable amount of savings! sure, i can get the 70-200 f4l and it would be great outdoors, but what if i need it for indoors? basketball games and volleyball would be prime examples of needing faster lenses so i really want the constant 2.8 aperture. this is where sigma comes in!
and having a black barrel would take away the inconspicuous looks that i would get from people. having taken the 450d with grip and the brick out, ive always gotten a "WOW thats a huge camera!" comment. so now i have a 7D gripped and the brick, im sure im getting a lot more of those comments...or somewhere along those lines. a white barrel lens just screams...look at me!
only thing i dont like is that it isnt weatherproofed. but i can deal with that, i have the 24-70L if i want to shoot in the rain.
another one i would keep my i eye is the 8-16 UWA.
well, i guess i have to start saving now if i want these lenses!
