Originally posted by AVANT Bit optimistic there I think. I seriously doubt that a DA* will be able to replace good primes and still have equal or better IQ.
Actually there are several good zooms these days which are as good as primes for at least some of their focal length range. The Canon 70-200 F4 is an example. Computer design has made high quality zoom optics a possibility.
Primes can have a small speed advantage, sometimes better bokeh because they require less correction and better contrast/less flare because they have fewer elements, but in a lot of cases you would never notice in an actual print especially at F4 or smaller apertures.
Look at the MTF figures for the Tokina 50-135 on Photozone - it is unlikely you will find a sharper prime.
As much as I love the Ltds for their colour and bokeh, a lot of my work is done with zooms and its pretty close.