My race number would be #1.
Cos I'd win everything
Ok, maybe not....errrrr....I'd say 26 because thats my birthday, but Evil Pedrosa has that...maybe number 20, since thats the age I passed my motorcycle test, or 127, since the 12/7 is the day I passed my test.
Or, I could be dead boring and use a scientific constant, avogadro's number:
6.022 x 10^23
Since that number is something I use all the time.
Matt