I finally finished putting together the E3 2007 theme for piano. It is fairly difficult to play but it is still possible. I went to my old "Halo Main Theme Extended Maw Version" transcription and added parts from the E307 trailer. There are a few mistakes that I could not fix but overall I think it sounds pretty good. The file is for Finale Printmusic 2009. Don't have it? Use this link to find out how to get it:

http://rampancy.net/blog/spartan182/12/11/2008/How_Open_MUS_Files

Update: I fixed and added some missing parts from Mike Poe's full score transcription of this song. I have also arranged One Final Effort for piano and have posted it here as well.

So you should see three files:
Halo 3 E307 Trailer full (The full score by Mike Poe and edited by me)
Halo 3 E307 Trailer Piano (My transcription for piano only)
Halo 3 One Final Effort (I added the beginning and other parts that were cut out from the E307 trailer)

Enjoy the music! Leave a comment or send me a message if you're having trouble with the file. Consider this as my Christmas gift! Merry Christmas everyone!!!