If you already get EPA or better in your current automobiles, then I assume that you know how to drive a car in a reasonable manner, in order to get good mileage. Therefore I would say that either version of the HCH would suit you well.

Purchasing the HCH-I would save you a fair amount of cash. Purchasing the HCH-II would give you more flash (hey I'm a poet). But I think, given your driving style, that the issue boils down to saving money (HCH-I) versus the newer/cooler/sleeker HCH-II.

And for what it's worth, I also prefer the styling of 2002-2005 Civics. But that's just my opinion.