Zoom or Prime

[Anbesol]

So on my wide end, I'm equipped with a 24-50 f4 and a 50 f1.7, I rarely use the 24-50, and primarily because in most wide angle shooting situations I want the bokeh and the light capability of the 50. As such I really stick with the 50 more, but of course I miss the wider angles then. I've been thinking about the Tamron 28-70 f2.8, but then I got to thinking about a wider prime instead, sacrificing range for speed and quality. Maybe the Sigma 24mm f1.8, or the Sigma 30mm f1.4. Has anybody any experience with these? How is the bokeh, and hte performance compared to the 28-70? I want some good portrait performance, so the importance of range may override the importance of the speed and bokeh of a fast prime. If I get the primes, I will also be adding the Minolta 35-70 f4, perfect portrait range and you can pick those up for pennies any more, but not if I get the 28-70f2.8 (then whats the point).Thoughts?

I've also thought a little bit about the Zeiss, but, well, money is an object and $1300 is quite a chunk.

Yay for tax rebates! ;)