#1 iChat Mobile Video - I told my brother last August about this idea. A two sided camera on the phone so you can take pictures or record video from either side. The cool thing about this is this makes it possible to have video chat on your phone over a wifi or 3G network. I would like this so I can show my parents live video of their grand daughter playing with her toys rather than just sitting in front of the computer.
#2 To dos - Where are they on the iPhone and why haven't they been implemented already? I just need basic to do lists that can sync from my Mac.
#3 Notes sync - I use the notes on my iPhone all the time for jotting stuff down or even taking notes during some meetings. I'm getting pretty good at typing. :-) However the notes on my Mac and the notes on my Phone are separate and can't talk or be grouped together. Why is that?
#4 Other syncing options - I would pay for .Mac if it included wireless syncing of my contacts, calendar, to dos, notes, etc. All of these things can be easily synced with little data needing transferred. Battery may drain a bit more but I think that can be negated pretty easily with settings.
I would also like to see some sort of 802.11n implementation in the next version of the iPhone - then I won't need to keep a 802.11g wireless router around just for my phone. Using the N standard would also allow you to quickly sync without having to connect to the computer. I usually charge my phone overnight next to my bed so the less syncing of minor things like contacts, calendars, etc. with a cable the better. We have wireless, lets use it.
#6 RSS Reader - I use NewsGator but a native app would be fantastic. Hopefully NewsGator will have an almost free version when the software is updated in June.
#5 Apple TV remote - Ability to use my iPhone/iPod Touch as an AppleTV remote. Choose movies, control volume
#6 iCal mobile - I like using the Calendar application on the iPhone. It works great but it could use a little bit of polish. For instance, when entering a Location for an event it would be great to query the addresses in the contact list such as "My House", "Dave's work", "Canister Office", etc. Then you can get directions later if you don't remember how to get there. The integration saves typing and allows you to easily get a map to your event if you need one. Also as stated above calendars should sync in realtime with .Mac or some other service (Exchange users will have this functionality in June with the 2.0 software release)
#7 Photos - Send photos to services other than .Mac such as Flickr, PicasaWeb, etc.
#8 Weather - I like the simple weather application most of the time. I would like to be able to see more details however. Perhaps allowing to scroll down or open up details for today with radar, severe weather warnings, and hour-by-hour forecasts would be very nice. Weather Underground has a web app for the iPhone that has the data but not as slick an interface. A combination of the two would be great. Also in a future version of the iPhone with GPS, realtime weather from the nearest weather station would be awesome. There are a couple of PWS (personal weather stations) by my house but I don't know which is the closest. If it could choose the closest based on my GPS location that would be ideal.
#9 GPS - Google maps is there. It does step by step directions already. I hope that version 2.0 of Google Maps (on the iPhone) will be able to be a real GPS navigator complete with voice directions (OS X has quite a few nice voices already) and some sort of 3D view for real-time tracking.
Leave a comment if you have any other suggestions. I've left out most of the 3rd party applications such as games and specific apps that 95% of the people won't use. Leave your suggestions anyway.