as far as the VX, it is a car that can easily get 45+ mpg and it seats 4 and has no batteries to replace like hybrids. that commands a premium price in todays market. that is why I drive a cavalier.
as far as the smart, I like it but it has it's draw backs. 2 people....that's it. no exceptions. that is a big one for me right now. also, you can get your honda better. my wife has an element and has done as good as 25 mpg on a tank of close to 300 miles and averages around 23 or so. she does have a grill block but that is relatively new. also hers is 4wd as well along with an auto trans.
there are some tips in the "201 tips to save gas" at the top of the page. it is a good read. some of the info is up for debate but it is a good place to start. one thing that will help out tremendously is buying a scangauge. it will tell you your MPG in real time so you can see what it sucking gas and what is not. go to www.scangauge.com
and check them out. that helped me the most. also, check out my gas log. you may want to consider a cavalier. you can get a descent one right now for around 3k or so and it will still be pretty new. they run cheap.
good luck to you.