Bolt, if he's a very hyper cat! =P

Or Quetzalcoatl.

Not Gray... too obvious.

You want something longer that can shorten into many things, for more mileage, like how Elizabeth can turn into Lisa, Eliza, Beth, Liz, etc. But in your case, something like:

Gray V. Robinson. You can call him Gray, Gravy, or Mr. Robinson. Feel free to pick a different last name.

Or you can always go with Prince Paul Orestes Atreides. You can call him Paul, Prince, the Prince, Usul, or Muad'Dib, but don't say it too loud.

William Jefferson Clinton (aka William Jefferson Blythe III) is really good. You can call him Bill, Slick Willy, The Comeback Kid, The First Black President, Teflon Bill, or Bubba.

I know from experience that naming pets after presidents makes them act more presidential and awesome. I once had a guinea pig and named him Abraham Lincoln (we saved him right around Lincoln's birthday), and we could call him Abe for short, and say "That'll do guinea pig, that'll do."

MY cat name is CAT

 Yes. And then blame him for everything

lighting since you like to use it so much to zap our asses in MK !

LOL cat!

That or "Ash".
"Ash" would fit his color. Buy him a small hat, give him a small yarn pokeball and you can teach him to dance to the Pokemon theme song.
How awesome would that be?

*dun dun dun*
I wanna be the very best! ^_^

Any of these are good.  Salami is another good choice.

Ash
Rocky
Hudson

Or perhaps you could just move away from the color theme and name him George in honor of the late Mr. Carlin.

Call it Chairman, as in Chairman Meow

Or Karl Marx. Cats are definitely communists.

tombi123 said: Call it Chairman, as in Chairman Meow Or Karl Marx. Cats are definitely communists.

Hahaha, close, but no cigar.

It's Chairman Meow and KARL BARX.

You see, dogs invented communism, and cats did it wrong.

I know, 'cuz I made this exact joke in 1999 when I was 16.

EDIT: And don't forget Poochie Minh or Fidel Catstro.  (Sorry.)