So does anyone still have the Beta installed on their Xbox? I do and sometimes I try to launch it hoping that one day it will.
I like to keep betas out of some weird sense of sentimentality.
Pretty sure I still have the Reach Beta kicking around on my 360.
Just delete them.
They are imprinted in your download history forever.
If you feel strange you can even download them again, though what would be the point in that. 