I'm looking at purchasing a portable NAV unit that was just introduced to the market a few months ago, called the RoadMentor. It's the same idea as the Street Pilot but takes it to the next level with a larger, high-res color touch screen (also button operation), with hi-fidelity sound, high speed processor, and a 1 sec refresh rate. It's completely portable between vehicles, with a built in antenna. Best of all is that not only does it perform like a high end, installed unit, but the price is only $499!!!
They just started to sell it at www.bimmian.com
, and they have excellent info on their site plus an online demo (huge file though, so make sure you have high speed if you want to download it). Bimmian is selling them for $499 with one map disk included (seven are required to cover the entire U.S. and Canada, and Bimmian sells them for $99 each).
Duo Electronics is also selling them LINK
for $499, but all seven disks are included
for that price, and they will ship anywhere in the U.S. for free ($10 to Canada via Global Priority Mail, which means a flat $5 Customs handling fee to the receiver from Canada Post rather than the estimated $150 gouging you will get from UPS)
All in all, it looks like an excellent device for the price, from a major overseas manufacturer of GPS equipment (Polstar). They've done their homework well.