I predict that there will not be a motion control announcement for the xbox360
I predict that if they do talk about the 720 (which I doubt they will), it will have motion control
I predict Halo 4, gears 3
I predict MS will go after the casual gamer with more along the lines of Lips, You're in the movies.
I predict Rare's new game will target ze casualz
I predict the announcement of hardware revisions. Arcade gets 512mb of memory, pro gets 80gb. Elite gets something besides just a harddrive upgrade

Edit: moar predictions

MGS4, Goldeneye, Perfect Dark (N64 game) port/remake, FFvXIII for the 360 will all not exist.

I predict people will be upset when the above occurs, because they have already convinced themselves that they do exist

Open with stats how the 360 is the best console blah blah and other random facts and then they will talk about alan wake!!! then it will be EPICs turn to announce new IP and then it will be time for AC2 and then MW2. Then we will hear about Lips and a new Scene it game. Then a Perfect Dark XBLA game remake. After that we will hear about forza 3 and then Halo ODST. Then comes Splinter cell conviction. Then it will be Mass Effect 2 and then motion control along with some other new game.

I also predict them to drop the arcade to $179.99 the Pro to $250 and they will phase out the Elite version. Make it a limited edition. They will drop the price to $350 for the elite until inventory is cleared out

I don't believe Gears 3 will be shown at E3. I believe that BIG Halo ODST will be done, including more video, with comments for people to try it out on the floor. There will be other news also, and the 5 minute surprise will be revealed. I expect more Live Arcade stuff will be mentioned, discussion of total content, and a bit of a blurb pushing both Live Community games, and people developing for them. You will get the Live Arcade/Community game montage.

Also, expect the unexpected.

Killer Instinct 3!!

-Kojima's new game
-Gears 3
-New halo game
-Square enix game of some sort
-Itagaki's new game
-Mistwalker's next Project
-Lionhead's new game

Overall game highlights:

Lionhead's new thang
Epic's new thing -- not Gears 3
Splinter Cell
Alan Wake
Forza 3
Halo ODST, possibly another Halo teased
new Tony Hawk game with something exclusive to MS
Some kind of exclusive DLC for Modern Warfare 2
MGS 5 or some series spin off multiplat, right at the end

Personal highlights:

Mistwalker's new game shown off

Kingdom Under Fire II (I hope!)