I'm with you on 4. I also have .mov (quicktime) files from a camera, they don't work either. Nokia, get us some codecs, please... as it is now one of the potentially great selling points ("extra independent SD slot, preview your camera video files easily!") doesn't work.

What I still use my T3 (PDA) for is mostly:
- Avantgo (the rss feed in the N800 is a bit rudimentary compared to Avantgo)
- Contacts (the T3 version is perfect for what I need it for)
- Calendar (I don't need calendar sync. functionality, I maintain it all on the T3)
- Todo-list (my shopping list, mostly)
- Simple calculator (for this app. the slight latency time for loading it in the N800 bothers me, the T3 calc starts instantly.)
- Google maps (the native application on the T3 utilizes the screen estate way better than using the browser to access maps.google.com on the N800)
- Keyring (password protector app.)
- KMeteo (that Accuweather app. on the N800 seems to be totally US centric. Apparently there's a weather app. in Maemo in the mistral repo, haven't tried that one yet. Coming to bora?)
- Offline email (while on the road I use N800/gmail in browser most of the time, through wi-fi or gprs, but sometimes it's ok to just sync gmail to my T3 through pop)
- Timesheet program (I've noticed there is one for the Nokia but I haven't checked it out so I don't know if it would fulfill my needs)
- MetrO program (this could possibly be ported to the N800, but the MetrO guys would have to decide on that)
- Watching those movies that the N800 can't display (which is just about everything I've got, on any card..)

Possibly some of the T3 uses could at some stage be taken over by the N800.