Geometry wars/Braid - Both are excellent arcade games.
Braid indeed is a great game.
There are more arcade games you may enjoy:-
Max and the Magic MarkerMadballs in Babo Invasion
Duke Nukem 3D
I bought those three games and beat them all when they first came out on XBLA...they were actually the first video games I ever played.
Oh, yes the original Doom is ****ing awesome too.
[Edited by Paradox, 5/20/2010 8:18:17 PM]