Most of the GPS receivers I spotlight are of the low-end, tiny-screen variety. Not so the TomTom GO 510, which features a 4-inch widescreen, a hands-free Bluetooth speakerphone, a built-in light sensor (which automatically dims the screen when it's dark out), optional real-time traffic and road conditions (you get a free one-month trial), support for TomTom's PLUS services (like downloadable voices and map updates)--shall I go on? In short, it's a pretty sweet GPS, and eCost has manufacturer-recertified models on sale for $138 (after a $49 mail-in rebate).
Like any good bargain shopper, you'll no doubt want to check out CNET's review of the TomTom GO 510. Alas, there isn't one, though a few dozen users rated it just 5.8 out of 10. Not a particularly good score, though most of the complaints had to do with reliability (when your GPS dies, you tend to leave a lower score). Because you'll be getting a recertified unit, you're probably less likely to experience any such problems. And you get a one-year warranty from TomTom, so the risk is pretty minimal.