I agree with the OTR suggestion. You'll want to stay south of Liberty on Vine street for the night scene - Quan Hapa, Kaze, The Lackman (no food), Bakersfield all have great drinks and most have great food. Fun night scene. Main street has a lot of bars, but they've been overrun with college kids of late. It might be different since classes just go out for the summer. If that's the case, Neon's has a great outdoor space and Japp's has great cocktails. Covington's Old KY bourbon bar has a great bourbon selection and cocktails, but is a bit pricey (if you're looking for a KY option). Northside and OTR are the heart of the current urban renewal. Check out Shake It Records in Northside if you're looking for vinyl.
The Comet in Northside has good burritos and no cover shows and is filled with colorful locals. The Banks is pretty and nice for walking around. The Moerlein Lager house has good food and a great view of the city and is directly adjacent to the stadium. It's a bit pricey, but is certainly the most interesting option.
Tucker's in OTR offers a great diner breakfast; you might see me there on Sunday if you stop by. There's a place called Virgil's Cafe in Covington that was recently featured on Diners, Drive-Ins, and Dives. I've not been, but I've heard good things from people I trust. Enjoy your visit!