I'm probably asking for way too much, but...
I don't have an iPhone. Not yet, at least. But everyone I know and their mother does, so my purchasing one is, of course, inevitable. I'd like to see:
-Video Camera. Possibly second camera (iSight) in the front side for iChat AV. Yeah, I know this sounds like crazy talk, but a guy can dream, right?
-Better speakerphone. I've talked on a friend's iPhone thru its speakerphone and I was not impressed.
-I heard iPhone doesn't have just a regular phone ring. I hate ringtones.
-More widgets. It'd be great to get more of the standard widgets you get with OS X (Converter, Translator, Dictionary). Also, I use Piano Chords and Guitar Chords widgets a lot. It'd be great to have them on the go. A tuner and metronome wouldn't hurt either.
-Games, games, games. Sudoku, Minesweeper, Solitaire, Texas Hold 'Em. Nothing terribly complex, just some good time killers. No web apps games, either. I'm talking games you can play while untethered to the net. Say for example you're on a plane and want to kill some time without killing everyone...
-Ability to sync notes with a computer. I heard you can't do this either. I sync my grocery list to my 3G iPod. It's good times.
-iWork Mobile with similar features to Microsuck Office Mobile, or some sort of mobile office suite.
-iLife Mobile. Not talking anything crazy, just the ability to do simple edits to clips, pics and sound bits.
Say you have a minute long video clip, but only want the last 10 seconds of it. iMovie Mobile lets you trim the front back, or even middle of the clip. Maybe even add a soundtrack and titles to it.
Next you have some pics you'd like to show people, but want to show them in b&w or sepia. iPhoto Mobile lets you do this, plus crop and possibly add text to the photos.
Some of you have probably seen iBand on youtube. This made me think the possibilities are truly endless. Say you have a tune in your head. Garageband Mobile lets you lay down a simple software instrument track, then add a vocal track using the iPhone's mic. Yeah, you're not gonna get anything professional, but one could at least create and mix some rough tracks that could later be opened and refined in Garageband. As a wannabe musician, this would be sweeeeet!
Lastly, say you want to put some pics, clips, or sound bits up on a .Mac Web Gallery for the world to see & hear. iWeb Mobile could help you do just that. Or perhaps add a new page to your existing site or update your .Mac blog. I know while traveling or road tripping it can be fun to keep friends and family up to date. This would be a great way to do just that.
-Sync/Backup/File Transer from iPhone to .Mac (or vice versa) would be rad as well. Yes, rad.
-GPS and a dock for your car.
-3G of course.
-Most of the stuff richimages mentioned. That seems way more realistic than all the nonsense I just mentioned.
Word.