I've had my company car (a Toyota Prius) for four years now and it's going back soon. The car has been utterly reliable – it's never broken. The fuel economy is good, the noise it produces is very good, and it fits Adrian Hollister + family & dog with no problems. The down side is that it's quite expensive for a company car. To help me decide I've test driven a couple of other cars – the BMW 320d, an X type Jag, and one of the new Ford Focus slightly more efficient 1.6D cars.
The beemer was just boring. Boring boring boring. No sat nav, no… well anything. It felt like the seats were optional, the noise was terrible – tractors down my road are much quieter, and the fuel economy worse than the Prius (with the same driving style and roads). The Jag just felt cramped and the family decided against it. The Focus seems smaller than the Prius and again it came with no basic's (my personal opinion is that sat nav and bluetooth integration are mandatory and actually very cheap for the manufacturers to provide). Fuel economy was great, so overall it's OK but nothing stunning.
Disheartened by the marketing hype on the BMW and the massive cost of the add-on's for both the BMW 320d and the Ford Focus I gave up for a bit. We had a quick look at a C30, but it's too small and CO2 output is very high; the same seems to apply to most of the other cars we looked at that would fit our family.
So what was the decision in the end? Well we are getting another Prius. The reasons in order of preference: Sat Nav, Bluetooth built-in, not waking up the family driving away in the morning (cos it's so darn quiet), watching the tyre fitters trying to work out how to drive the car on to the ramp (seriously – this is a hoot), low CO2, utterly reliable and good fuel economy.