I love my StreetPilot c550 - in fact, it's my current Editor's Choice GPS and the unit I have installed in my car right now. I've been using it for weeks now and can re-verify my initial findings that this is the GPS to beat right now. Garmin is an innovation company and commands a lot of respect in the industry, but there are a few things I really wish Garmin would add that would really make a great product even better: (and all three could be easily added via a firmware update) In order of importance:

1. Faster re-routing when you are off course (or a manual button to force an immediate re-route if the unit is taking too long). Sometimes when you drive off course, the c550 takes too long to re-route you. This is especially true in urban environmnts, where you need to make the next turn quickly, or during highway interchanges.
2. Cell phone signal strength indicator when using the phone via Bluetooth. It's nice to be able to see your cell phone signal strength while using the c550 as a speakerphone without having to look at your cell phone.
3. GPS Signal strength indicator on the map and while navigating. I'm sure this is a deliberate choice by Garmin not to include the signal strength indicator on the map view or while navigating, but I think it's very useful to know if the unit is routing you accurately or not.
4. A Bluetooth update that would allow you to answer an incoming call either on the c550's speakerphone OR your cell phone's handset. There are times when you don't want to use the speakerphone (i.e. when others are in the car), and it's annoying to have to answer on speakerphone and then activate the handset to talk in private. Perhaps adding a button so that when an incoming call starts to ring, you can tap on the screen "Answer - Speakerphone", "Answer-Handset", or "Ignore".

Add those 4 items, and the c550 will be even better.