I've got an Alpine CDA-9835 and love it.
You didn't say how much you were willing to spend, and my best guess is you wouldnt want to spend as much as this costs (its not cheap), but you asked for some advice, and Alpine make killer head units.. It has about every feature you can imagine right down to digital time correction to adjust each speaker delay in milliseconds to adjust sound imaging. This may be a lot more than what youre looking for, but if you're willing go all out you won't be disappointed. It won Premium Head Unit of the Year 2004
Read some reviews too.. you wouldn't be dissapointed!