Nokia's just announced what it's calling the "world's thinnest smartphone," the E55. They're calling it a compact QWERTY keyboard, but let's be honest, it's SureType. According to the press release, it's got 28 days of standby time in its battery, as well as full Nokia Maps and assisted GPS with integration. Look for it this summer for 265 euros unsubsidized.
Update: New details from the fact sheet. The 28 days of standby applies to GSM -- it drops to 19 days on WCDMA -- and talk time for GSM / WCDMA is 8 and 6 hours, respectively. The phone sports a 2.4-inch QVGA screen, 3.2 megapixel camera, 3.5 mm headphone jack, 802.11 b/g, EGPRS, and Bluetooth 2.0.