I recently purchased a 2003 Honda Civic Hybrid, though I had to get rid of my ever so fun to drive G35 the car is remarkable with respect to fuel efficiency. The layout of the car is simple, just like all Hondas. The power is on the low side, but lets face, we buy these cars for one reason and that's fuel economy. I wouldn't care if I had to get out and push the car up a hill (which it almost seems like I have to do living in Upstate NY), as long as I'm getting my 50 MPG let every other car pass me on the road. I'm purchasing a new set of Cooper GFE (LRR) tires and I'm hoping to eek out a few more MPG.
The one thing I find interesting is when the IMA system is engaged the estimate fuel economy drops. I would expect that when the electric motor kicks in the fuel economy would increase similar to other hybrids.