The Hummer Vs Prius myth is debunked here by the Pacific Institute's Integrity of Science initiative:
http://www.pacinst.org/topics/integrity_of_science/case_studies/hummer_vs_prius.pdf

In the UK the Prius drivetrain and batteries are covered by a 8 year warrany. Toyota have also said they will recycle the batteries. However what drove to opt for a Prius for my next company car was the GBP£900 tax saving per year, with the car expected to be in my life for the next four years that will add up nicely and that is before the gas mileage is taken into account. That tax saving was versus a Honda F-RV (Small SUV, the Diesel version of which has a combined ~37MPG).

The other front runner for me was a BMW 3 Series Touring with the 1.8 litre Diesel which claims fuel consumption of just under 60MPG. The 2.0 litre Diesel is only marginally less. All courtesy of BMW's EfficientDynamics programme. If they options list hadn't been so damn pricey I would have opted for the BMW.