As far as coasters go, your best bets for short waits are the rides other than the big 4 (MF, Magnum, Raptor, and Mantis). Since you're goign in July, the coasters that were walk-ons earlier in the year (and now) will have approximately 15-20 minute waits. One ride to watch out for is Wildcat. It has pretty horrible capacity, and what appears to be a short wait may actually set you back 45 minutes or so.
Other thrill rides that you can enjoy with a short wait are Chaos, Demon Drop, and the *up* side of Power Tower (actually my preference because of the pop of air at the top).
Hope this helps...I'll be glad to help you with any other questions you may have.