As a Christmas Present to myself I installed a Bluetooth radio in my non-JBL 2003. I am not a fan of touchscreen units, I'm not really sure why everyone likes them so much. They are 3x as expensive, and the interface is usually cheap and annoying. So I went with a mid-level dual din Kenwood like I had in my 3rd gen. It has variable color lighting and looks great in the dash. (Looks bad in these pictures with the flash on but looks good in person.) Pleased with the sound so far. Total price $195 with the extras.
Purchased from Crutchfield which included the wiring harness, dash kit, and steering wheel controls. Turns out that the radio came with a Toyota trim piece already in the box so I didn't need to dash kit, but I ended up breaking it during installation so I did end up using the extra dash kit... glad I bought it.
Although I've installed 4 stereos before, this install was kind of a pain in the butt. Mostly because of the steering wheel controls. Definitely worth it though.
The car has some Sony Xplods from the previous owner but I plan to eventually replace the front speakers with nicer 6x9 components and power them with a higher power amp using the stereo's RCA outputs (this stereo puts out 22 watts x4 RMS, which is pretty good, but 75 will be better).
I wish this car had the factory subwoofer so I could stuff a nice 8 inch-er in there. Might end up getting a slim under-seat powered sub. Can't spare my trunk space for a big system.