Of all of them, my most favorite is Edge's theme: Metalingus - Alterbridge.
And of others, I like Jeff Hardy's song : No More Words - Endeverafter.
I don't remember another, but my favorites is this songs.
My favorite is Rey Mysterio's.
I don't know why, maybe because he's my favorite wrestler but the song itself is very cool too.
Then I like several other entrance songs such as DX's, Edge's and John Cena's songs.