Welcome to the board. I'm down in Oceanside.
If you have the money for a 600+ go for it. 250 is enough, like everyone else has said, but it's nice to have the extra power. Imagine buying a Dodge Neon knowing you could own a Dodge Viper. The Neon is economical, easy to maintain and cheap, but you'll eventually want the Viper. Best way I can put it.
I bought my first bike (09' 250R) from a friend a month ago and love it, but I'd be lying if I said I didn't want a larger bike. For now this will do, but I will upgrade in the future.