need input on lens collection

[rrwilliams64]

This is my stable of lenses at the moment

D90
Nikon 18-70 f/3.5-4.5
Nikon 50mm f/1.8
Nikon 85mm f/1.8
Nikon 55-200

My usual walkaround lens is the 18-70. I have a good copy, vignetting is very minimal on mine and it does good work given adequate light, I feel its sharpness and contrast is underrated when lenses are debated (again, at least my copy )

I break out my fifty for low light indoor work, portraits, ect and was looking at the Nikon 35mm f/1.8G AF-S to add to my bag to complement my 50.
I then had an epiphany, and here's where I would like some input...(while acknowledging the IQ of primes, I also dont want to end up having that many lenses..also, I love my 85 f1.8 and it fills a niche my other lenses dont, it stays regardless
...My "epiphany" was to get the Tamron 17-50 f2.8, rather than having two primes in that FL and still missing out on a fast lens for the wide end, barring yet another acquisition. Yes, I realize the primes are the ideal, but I also know the Tammy, given a good copy, is quite the performer (I had one when I was a canon shooter). In this scenario I would sell the 50, the 18-70 and not get the new 35 f/1.8G

Now, I dont mind switching lenses, (matter a fact, I have a severe case of LBA ) but at the same time I'm not the uber-pixel peeper and would like to have a more "efficient" lens collection. That said, keep my 18-70 and include the 35 f1.8?... or would I be sacrificing IQ if I downsized to the Tamron 17-50, selling the 18-70 and the 50, only keeping the 85 f1.8 and the 55-200 for the minimal tele work I do? I realize its a subjective question....but I often refer tothe knowledge base of my fellow posters. Given the above cited lenses, both in my bag and potentially gotten, what would others do. Just some anecdotal input would be excellent...

Note, I have a cross section of shooting preferences...a smorgasbord, but I'm really looking at my situationfor indoor, low light shots.

Thnx

[TCav]

The unstabilized (non-VC) Tamron 17-50/2.8 is quite a good lens, but the stabilized version isn't as good. If you want a stabilized fast standard zoom, the Sigma migh tbe a better choice.

[tizeye]

I have the Tamron 17-50 non-stabilized version and it is an excellent lens. In the reviews, it is sharper than both the Tamron and Sigma with their versions of stabilization. It raises the question...why have stabilization in a 50 and below? Even the much heavier Nikon 17--55 isn't stabilized.

Next question...why sell the 50 1.8? How much are you going to get for something that retails for just over $100? You will save that much in the price difference between the two Tamron versions.