I had a similar predicament about 3 months ago, only backwards. I have a 32gb iPod touch and wanted a smartphone, but could not get ATT, so iPhone was out of the running from the start. Anyway, enough about my thought processes; I bought myself a Blackberry Storm. Honestly, after that, I had little to no use for the non-regular-iPod functions of the iPod touch. It was pretty much relegated to Video and Music use only. About a week ago, I bought a new red 16gb nano, and it is AWESOME! I actually can't believe how much the iPod touch is missing in terms of media playback capabilities compared to these modern click wheel iPods. (My last click wheel iPod was the iPod 5g) It's almost incredible. Sure it doesn't have Wifi or the app store, but your Pre has data and its own app store. The only internet function I really used the touch for after I got the Blackberry was to buy songs on the iTunes store while mobile. That's really the only feature I miss on my nano, but I seldom used it anyway.
The Apple app store is nice, but it's not all that awesome. Seriously there are, 25,000 apps, and probably 2/3 of them do the same thing as another. Which really would bring the total number down to around 8,000 types of apps, of which you will probably only use around 5-6 apps daily (learned from experience), and if you don't play a lot of games, there really isn't a whole lot to get from the App Store at this point. Sure some apps are nice, like the Facebook iPhone app (much better than Blackberry and I don't think the Pre even has one) and BeeJive IM, but the big ones (like BeeJive) are actually available on other platforms too (there is a BeeJive for Blackberry).
I think you should seriously reconsider the nano and classic. The Classic may be a good choice if you just want no-frills pure storage space.
Also, the nano is so small you can carry both your Pre and Nano in your pocket without really even feeling the iPod. I know it's like that with my Storm.
