you really can't go wrong with the scion head unit...
It LOOKS stock, but sounds so much better than the stock CD player. On top of that, the steering wheel controls still work, the back-light on the single disc matches the interior perfect, and you can put ~150 MP3's on a single CD and play them with this head unit. I feel it was the best $100 I'd spent in a long time, and have no regrets doing the upgrade.
If you have any other questions, just let me know.