Nothing wrong with 480's. I have all 3 of mine in SLI watercooled and they run really cool and damn near silent.
I'm easily good for the next year and a half at the very least for running the latest games fully maxed in 1080p. (I play on my TV)
No need for me to upgrade to 580's, wait until next generation when theres a real upgrade. Most of the advantages of the 580's are nulled with watercooling. Sure they run faster, but my 3 480's are clocked at 900Mhz core.