Tomorrow, I'm supposed to be picking up a Tamron 17-50 f/2.8 locally for $300. It's in perfect condition, comes with a lens hood, caps, etc. Good choice? Right now, I have just my 50mm f/1.4. I'm trying to gear up for the wedding I'm shooting at the end of this month. I'm thinking the Tammy 17-50 and the Sigma 70-200 f/2.8 will be a good combination in conjunction with my 50/1.4. Thoughts?