I like Marvin... just because the term "android" always had an alien sounding aura too it and Marvin was used as an alien name in something I've seen/heard/read at some point in my life.
I think "kernel" is cool... "kernella" if it were to be female (or a future lady-friend).
Su
Sudo
Sudroid
Bash
Basher
Can't believe I haven't seen "Linus"..."Lindroid" as the female version.
"FroDro", although once froyo is old news the "fro" or "ginger" names wont sounds as cool so I think as a collective we should agree to not use build names as a mascot name.
I like Andy or any variation of that. It just seems like the obvious choice for Android central. But since that has been suggested numerous times I am going to suggest Mandy (my Android) or Froid.
Name it BRAVO. You can use its name in english & spanish. BRAVO for Android's ability to take on all platforms. BRAVO for going up against that Cupertino company. BRAVO for its ability to morph in to anything YOU want. Good luck everybody!