I know everyone is going to hate me for this one, but I am one of the few who believe gas taxes should be higher and/or a percentage (like sales tax).
For one, I would rather put the money into the government instead of oil company execs (of course, we then need to re-create the highway trust fund(s) instead of putting all the money into state general funds and other such nonsense).
Higher gas prices should also drive the market to more efficient vehicles, and push the development of new technology. I mean, my 65 pickup with a 390 gets 12 mpg, and a new pickup with a similarly sized engine gets what, 15?. Wow, what a huge increase in 40 years! (I know, it has less emissions...). A little truck like a ranger or s-10 actually gets worse mileage than it did ten or fifteen years ago. There are no new cars other than hybrids that get mileage like the old Geo Metros did (I will save my distaste for hybrids for later).
And if we put enough money into the trust funds to rebuild the interstate system (we pay for it one way or another anyway) on the way to developing signficantly better vehicles, all the better.
Of course, being a pavement/transportation engineer, I may be a little biased...
Travis