If you're willing to look at used guitars, I've found 3 different "Strats" that are at the top of your price range ($600), but were so far superior to most American Fenders that I've played:
ESP Vintage Plus - a late-'90s model, stock w/ Duncan pickups, Sperzel locking tuners and a comfortable slanted neck/heel joint.
Hamer Daytona - another '90s model, made in USA, beautiful finish, excellent sound.
G&L S-500 - a couple years old, I just played this one at a local store and wow, what a great guitar.
All of them: $600