If I wanted to buy a new car for an obscenely long highway commute, I would look hard at a Civic Hybrid. The drivetrain is set up a little better than the Prius for those conditions due to its band-style CVT which transmits power directly. The Prius uses an eCVT, which requires that some engine power be converted to electrical in order to control the gear ratio. Of course, HSD is tailor made for the stop&go cycle which would be harder on the Civic.

5-speed Insight would absolutely dominate, but I don't know how you would feel about the comfort level. That and the fact that it would be kind of hard to get. But you could be looking at 70mpg+ with a little effort.

Yes, the Insight will return higher numbers than the Prius, but the Prius is much more comfortable. I agree that the HCH I has more highway FE potential than the Prius due to the Honda Lean Burn technology. But if you prefer higher speeds, the Prius atkinson cycle and lower Cd will overtake the HCHI, which loses leanburn at 55-60 MPH. Perhaps an HCHI owner can confirm?

I had a '03 HCHI and it was VERY picky about lean burn. You're right about 55-60 mph, actually my "sweet spot" was 53 mph on a flat road. 70mph it would do around 39-43mpg depending on traffic. I'm doing a steady 36 mpg in my replacement car - Toyota Matrix (just did a 42mpg nonposted tank, lost receipt). The Matrix is roomier and IMO more comfortable than the HCHI. A very nice ride, roomy, & cheap.

**For the record and not to steer OT: the Matrix only got 42mpg because a friend was driving it behind a motorhome I bought and had to drive 300 miles to get home, I told him to draft since I was doing a steady 55-65 mph in very light traffic**

Fit or Yaris, but base = no cruise control. Avoid late VWs at all costs, a friend here is the GM of a large shop and says that these and Ford era Volvos are what pay the bills. And their forecourt is always full of the things....with the odd Benz or Peugeot in the mix.

Amen, We had a new 98 beetle, and it must have costed $3000 in maintenence and repairs over 3 years. Electrical problems galore!

Speed
 

At those speeds (65-70 at long distances), you need something light, MT, and aerodynamic (or hybrid).

Most modern, non-Diesel machines won't get you what you're looking for in the speed department, other than those with a low cD and friction (e.g. Hybrid).

Rumor has it that an Orthopedic Surgeon helped design the seats in the Prius-I (I can agree that someone knew what they were doing becuase they're really comfortable and supportive).

The clear winner for highway miles is the Insight, but for long-commutes, you may regret that decision as it beats the crap out of you. After crunching the numbers from the EPA on 2006 and 2007 MY cars vs. my own database of FE and reliability, for 45 MPG it looks like:

1. Prius I and II
2. Civic Hybrid I (manual)
3. Civic Hybrid I Automatic and HCH-II
4. Yaris 3-door Manual
5. Toyota Corolla Manual (almost any year, really)
6. Civic Automatic (06-07)

Honestly, Diesels are the way to go for highway miles -- but it's your call as to their reliability. Remember, there are many cars not on the list above that you can squeeze 45 mpg out of.

BTW, slow down! I know you have a long commute, but you could probably get a bigger, more comfortable car if you stay around 60 and/or drive with load -- meaning:

You're moving along at 60 mph with 20% throttle on level ground. You approach a descent: stay on the throttle at 20%. Now momentum gets you going up to 70, for example, down the hill. On the ascent up the next hill, keep that throttle right where it is and scrub-off some speed. You may go down into the 50's as far as speed goes, but your average speed will still be around 60, and you've saved a LOT of fuel. That technique has yielded me MUCH better highway FE. I've modified my cruise control to do just that, and it takes away the need to focus so much on the pedal pressure.

RH77

We took a road trip last summer with a Prius about 1000 miles round trip. We drove together at the same time. We kept having to stop for the Prius to fill up ;) Just kidding we had to stop anyway to eat, bathroom ect. But seriously we filled up on every third stop compared to the Prius. It was mostly highway / freeway driving and we averaged 56 for the entire trip while the Prius averaged just over 45 for the trip. I never rubbed it in and we didn't talk a lot about it, but the Prius divers wife eventually asked him why they didn't get a TDI ;)

Seriously though I think the Prius is a great car and we came really really close to buying one when we bought the TDI. The extra room in the back of the Wagon and the safety ratings and the ability to burn bio-diesel won us over. For highway driving I would choose the TDI for city commuting or stop and go driving I would choose the Prius.

If I was in that position. i would buy a Accord I4 or Camry and move on. Get the low to mid 30's and stay comphy.

As a owner of a 05 Accord Sedan and a 06 Civic Sedan. They are close in comfort. But a Civic isnt a Accord no matter how you cut it. TDI would be nice! If they didnt cost a arm/leg and left nut. And then either be great cars or shop ****s.

I can keep the Accord at a steady 34 mpg plus on the hwy. The Civic will turn in 42 mpg steady on the hwy. Air the tires up and keep the speed subsonic and I cant think of a Honda or Yota that wont get atleast epa.

Odd, I just got finish traveling for the holidays in a Prius, 450 miles @ 64.4 MPG with 4 people and bags. Speed at 60 MPH. Dan's assesment is right on for the Prius and it's comfortable. It does do much better in the city than highway though.

Ah yes at 60 maybe, we were going right about 71 indicates or 67-68 GPS wise. Oh we had 4 people in the TDI wagon (which starts out heavier), packed to the gills and the Prius had two people and luggage in the boot.