things I think is important (listed by importance):
1) ability to scroll rapidly in Photos and Music player (have over 3000 numbers... and will have more with the 32gb.)
2) Arrange media by the iD3 tag and/or it would be nice to be able to tag your media files (music and video) like your photos (with tags/genres you can edit yourself.)
3) ability to send files directly from File Manager
4) MMS (I do send quite alot of those. Nice and easy postcard)
5) re-arrange icons

Don't care about portrait mode... (think it's annoying that the screen rearranges if I tilt the phone...) Have disabled that on my flashed HD so it only works in browser... Hate that the iPod switches to that album flipper if tilted too much and same thing with the HD. But If others want it fine by me ( I just hope it will be optional)