Just a note on the tokina 28-70. Its not strictly speaking, a zoom lens. more like a varifocal. so you ll need to refocus each time you change the zoom setting to get the sharpest images. this is especially so between 28-35mm. i think this is what give the lens a bad name. i recently picked up the 28-70 2.6-2.8 II version with the lens hood bayonet. its surprisingly sharp and contrasty on the wide end, looses abit of contrast on the long end but performs beautifully for a zoom lens. I quite like the colours. its punchy but not overly so, and has a very film-like feel when set wide open.
f5.6 it works v well as an event lens as long as you remember to refocus when you change the FL