Multiperson Group Chat - You can't do it with people in the same game as you.

More BC Games - Larger list of Backwards Compatible games.

Clan Blade - Clan support for all games that have clan support.

Web Browse - Optional download in the marketplace so those that don't want it don't have to have it.

Faster Guide - The desktop with be much smoother and cleaner.

Vision Camera Features - A lot more features for the camera.

Disk Drive - When disk is in drive it'll say which game it in the disk drive.

Customizable Themes - able to put a different pic on each blade.

Friends List - able to add more friends

Multi Video Chat - would be fun to have 4 people in a room all with cameras talking

Video Messages - able to send a video message to your friends

Ad Deletion - Able to turn on or off the advertisments whether your 18 or not.

Arcade Demos - Not to appear under games played.

Open Tray - Open the disk tray from the dashboard when a game is in it.

Text Messages - Longer than 250 characters.

Away Messages - Like AIM. So it would say going out for dinner, etc.

Weather System - Somewhat like the Wii where you can see a forcast for your area.

Zune - More integration with the 360.

Video Codec - More support than just WMV.

Reply Message - Able to see the text that your friend replied to. so you can
remember what you said to them.

Save Vision Pics - Able to save a bunch of pics from your vision camera to the hard drive.

Groups/Clans - Be able to have groups on your friends list. like "real friends" and "GOW gods"

heres a link http://360unleashed.blog.ca/2007/03/19/xbox_360_spring_update_list~1936217