I've had an 03 for 3 years now. In my passing evaluation of the 06, I personally noted a few things:
- I like the look of the 06 better (subjective, yes)
- I think the auto-stop programming in the HCH II is better than the HCH I, in that it will auto-stop more frequently during stop-and-go traffic
- I like the fact it will go EV mode (at times) to maintain speed and not use the engine
- I like the audio controls on the steering wheel
- I like the idea of integrated sat radio (although we know this doesn't live up to it's billing and costs much more than advertised). In any event, and in-dash unit would be nice.

There may be more, but those are mine. That said, it was not enough for me to part with my 03, which I will drive at least until I see the HCH III (whatever that is - probably around 2010 ish).

I wish I could offer more of a comparison. However I will say I like my HCH I, and I do not regret owning it. Small inconveniences aside, it's a wonderful car.

If it were me in that scenario, unless I felt like I'd drive the HCH II for 7-10 years, I'd be strongly inclined to save the money and go with the HCH I, pay it off quick, own it for 4-5 years, then see what's out there. I think in another 5 years there may be some very cool options out there to choose from. That's just me.

*** Retired after 65,000 outstanding miles ***