So I'm in the market for a GPS system for my car. I've been using the integrated OnStar system, but it costs me an extra $10/month and I don't feel that I get that much value out of it (I only really use it when I don't know where I'm going because it interrupts the CD player so frustratingly, not to mention having to deal with people is increasingly less convenient and more frustrating.) I figure if I spend $250-$350 on a nav unit and it last 3 years, I'll get more use for less money.

I'm looking for a model with the following characteristics:

Must have:
--Slim profile. I'm putting this in the corner of the windshield, not the center. I don't want one of the big, clunky, old-style Garmins.
--Bluetooth with quality output. One of the most frustrating parts of an OnStar vehicle is that there's no Bluetooth support at all. Ideally, I'd like it to sync with my address book automatically.

Would prefer:
--Text-to-speech, especially entering addresses.
--Solid GUI with no interface hangs or freezes.

If anyone has any experience or information, I'd appreciate it.