I rented Nikon's 17-55mm f2.8 DX lens for a recent club photography, and I loved it. It made my job so much easier the entire night, just because I now have the zoom flexibility while only sacrificing about 0.8 f-stop compared to using a prime. I'm seriously considering buying one, but at the moment, my biggest qualm is that it's a DX lens. Eventually I want to move to an FX body. Is it silly to invest in this lens? I'm sure there's still a decent amount of life left to DX bodies. D300, the upcoming D400, etc. I don't really HAVE to move to FX. I'm not that pro. What do you think?