Smoother video playback
instead of using ‘Auto rotate’ on Media menu ‘Settings’
select either Landscape or Portrait,
using Auto rotate (I know it’s a nice idea but) really seems to makes videos stutter,
first select a video then press centre soft-key ‘View’ then before pressing ‘Play’ press left soft-key ‘Options’ choose landscape, press ‘Play
to choose another video press ‘Back’ then use left or right on D pad,
press centre soft-key to play,
normally the video plays in sync (unless play/pause is used then sync goes completely to fix this either restarted video or choose another)

They are a bit jerky anyway for first couple of seconds (compared to K800i) in Landscape mode until the progress bar and icons disappear then they play smooth (have tried all display options, guess a firmware update should fix this one!)
Something else give a slight speed-up on menus and general feel of the phone , choose a basic theme like Clarity and/or make sure you have a static backdrop picture instead of an animated one.
PS: Files tested are M3 encoded video 300Kbps, audio 96Kbps LC (which play smooth on K800i)
Another tip!
While watching any video, pressing the camera shutter button grabs a still picture of the current video frame (difference is it’s saved in picture folder, not photo folder!)
Just in case someone doesn’t know, if not wanting to use the ‘Media’ menu or touch key,
normal file folders are now located in the ‘Organizer’ menu (key ’0′ (zero) when on normal menu screen)
Some really cool new additions I found so far are:
1. When starting to type in a phone number in the standby screen, the phone searches through contacts (like on a Windows Mobile 6)
2. When on keylock, and receiving a file through Bluetooth, it automatically unlocks for one to accept the transfer…no need to press unlock before.