Just a comment about Ritz. I went into the one here in Manassas and the salesman wasn't helpful at all and made me feel bad about asking about a flash diffuser. He said that if I knew anything, I would know that Ritz wouldn't have that kid of equipment. He could have steered me to a place that actually had that item. I ended up ordering from Canon off the magazine. Now to help with your question, it's a matter of portraits and blur. If you only want your subject in sharp focus, the Tamron may be disappointing. You have to weigh the value of having a zoom and a true portrait lens. The Tamron is also really light (a plus). The 85 f1.8 is heavier and the 28-135 IS even heavier than that. Putting those lenses on your camera around your neck can be tiring. Add the large flash and a tripod sounds great.
SuzyView
Ritz is a joke. Your response should have been, "If you were a REAL photography shop you WOULD have that kind of equipment!" I went into a Ritz here in NH and asked about a battery grip for my Rebel T2 film camera. I had seen them online for about $36.00 at Adorama, B&H, and Abes of Maine... you know, the REAL photography stores...:P and the guy(kid is more like it) told me that it was a special order item that would take up to 6 weeks to get in and would cost me $120.00. He looked at me like I was lying when I said I could get it by the end of the week and for $40something with s/h. When I asked about prime lenses.. (the 50 f/1.4 and 85 f/1.8 in particular) he acted like I was behind in the times by saying that today's zooms are so superior to zooms of the past that primes are no longer being used by pro's.
He told me that I'd be better off with his Quantaray 28-70mm lens in terms of quality and flexibility than any prime lens. Needless to say, I bought my camera gear from Adorama and B&H. 

