I was tempted by the 17-55, but I refused to buy a lens that only worked with crop sensor cameras. I did it once with my 60mm Macro, but never again. When I go FF I don't want to have to deal with switching glass.
IMO, that's like stating, "I refuse to buy the BMW 760Li because it doens't have a towing package option, and I may buy a boat someday." I recommend getting the best lens for what you need to shoot, today, with the body that you have. Now, if you're getting a FF camera next month, that's one thing. But "I may go FF someday, maybe..." isn't a good reason to choose a less appropriate lens, IMO.
Consider the L-series lenses people suggest as general purpose zoom options for APS-C, and keep in mind that a 'general purpose zoom' covers wide angle to short telephoto:
- 24-70 I or II - no wide angle, good IQ, no IS
- 24-105 - no wide angle, good IQ
- 16-35 II - no tele, good IQ, no IS
- 17-40 - just ok IQ, no IS
The 17-55mm f/2.8 IS and 15-85mm f/3.5-5.6 IS fit the focal range definition of general purpose on APS-C, and offer excellent IQ (better than the L-series lenses listed above, with the probable exception of the 24-70 II, when comparing them on the same APS-C camera).
Both of those lenses hold their value like L-series lenses - buy one, use it for 2-3 years, and the way lens prices are increasing, you won't take much of a loss (I sold the 10-22mm a year after I bought it, for $50 less than I paid for it new from Amazon).
The only reasons I can see to use one of the L-series lenses are if you shoot both FF and APS-C, are buying FF very
soon, or have a 7D and require a weather sealed lens.