For the past two days I've been reading here and elsewhere about the Prius. We have an unusual commute and what I've been reading leads me to think that the Prius might not work for us financially. There's 3 totally different types of vehicles we are thinking about, the particular Prius I want being the most advanced and most expensive. I'd really like one if I can save enough on gas monthly to compensate for the higher acquisition cost. My commute is almost all highway - there's 3 stop signs and probably no more than 5 traffic lights. That's good news as far as I can figure out for good mpg. We are used to driving no more than 65 mph on the freeways, to keep our expenses down and can get EPA MPG or better numbers on what we currently own. Also good news, I think. The majority of the commute (about 50 miles of it) is full speed, not a lot of stop and go or slow and go traffic. However, 25 miles can be very slow and go. That's not so good. But the really bad news is that the commute goes between sea level and 6,000 feet elevation. For those that are familiar with Southern California - we drive the Sepulveda Pass, Neuhall Pass and the Grapevine every day (75 miles one-way). We also make frequent trips to see relatives in Vegas, so in winter I'll be driving in below freezing weather and in summer it can be over 100F. Right now we drive a 2007 Honda Fit (259,000 miles) and can consistently get 34-37 mpg, have even gotten over 40 mpg on some trips to Vegas. Replacing it with another Fit is definitely a possibility but there's a few things that the particular Prius model I'm looking at offers that the Fit doesn't (a quieter cabin, for one). I figure that if I can get a consistent 46 mpg with the Prius (Prius 3 with solar roof/nav package) I'd break even money-wise and have a car with more features. However, if that's out of range (and I could see how it might be) I'll get another Fit because our budget would be too strained and the Fit is acceptable to us. So what kind of milage could I expect to get on a relatively consistent basis, given my unusual, extreme commute? Is there something I haven't thought about that could influence our decision one way or the other? The various threads I've read helped convince my other half that battery life won't be a concern for a car we'll probably keep 5 years/250-300k miles. Thanks very much in advance for any experiences/information you can give me.