All diesel fuels wax, including low sulphur.
Hybrid cars are designed for "average" driving usage. If your balance of town driving, open roads and high speeds is right, it will work beautifully : battery only around town, engine plus recharging battery on the open road and engine plus battery power at high speed. If you spend too much time on motorways/freeways, then the little petrol engine will be called upon to recharge the batteries as well as power the car with no reserve and your consumption will fall into the low teens (UK figures for gallons; may be single figures for US gallons).
People who drive 50/50 urban and out-of-town but rarely go over 60mph will find the Prius economical. If you do high mileages on motorways, it will cost (and be noisy). If you spend a lot of time around town, the petrol motor will kick in eventually to recharge the batteries.
The most eco-friendly solution at present is a small diesel car on fuel grounds alone. Taking into account the production and disposal costs, the hybrids are way down the league.
I have been driven in an early Lexus hybrid and I'm fascinated why more of these are not involved in accidents. The fooling around you do with the extra power gauges on the dash to maximise use of the electric motor and prevent the petrol engine cutting in, the constant watching of the power reserve indicator..... Gadgets!