I'd get an Alpine head-unit. Most come with all the features you're looking for and typically are all-red in color. $150-200 will net you a nice one. Just look around a bit, most sites list all the features a radio has. The most you might have to do is buy a cord that will plug into the front of rear of the radio to connect USB devices or iPods.
Aftermarket radios typically come in two sizes: single-din and double-din
You want a single-din, and you'll be able to buy a GM mounting bracket that will fit the radio which will then fit into your dash.
As far as wiring, you can buy a GM wiring harness that will work with any aftermarket radio. There will be wires coming off the plug that comes with the radio, but all the colors on both harnesses match up and all you'll have to do is pair them and make sure they'll stay secure and un-exposed.
