I have two iDevices. :s One of them technically doesn't belong to me (yay work phone), but yeah.
I think Apple fixed that wi-fi issue in 4.1. I have an iPod touch 4th gen and the only things that really drain the battery quickly are heavy Internet usage, games, and, to a lesser extent, the screen being on. Downloading my Rhapsody library onto the device, for instance, murdered my poor battery. That said, I think Apple calculates battery drain based on what you're doing, since it went from being barely in the red to a few pixels above it after I was finished.
I also have a jailbroken iPhone 3G running 3.1.3 that I have through my company. I was actually given permission to jailbreak it after my boss bought an iPhone 4, just to see how much of its functionality I could replicate running iOS 3 (the answer was: just about everything! The lack of RAM and slow CPU make you quickly realize why Apple didn't allow those things on that device, though). I think I have a screenshot of the nearly-accurate WinterBoard theme I threw together*.
It's funny, I used to always think that the iPhone was a speedy device. Certainly not a speed demon after upgrading it to iOS 3, but still quick. Now that I have the Touch the 3G feels sluggish. Funny how that works.
*The button labels cannot be pushed up/down to the same spot that they are in on iOS 4. Also, icon shadows can't be done properly using just WinterBoard. You can hack something together that makes it look even closer, but I think my theme is the closest that you can possibly get while still being able to use the device normally.
Edit: Also, I'm "spectere at gmail dot com" on GameCenter. ADD MEH.