If you are worried about future costs then id rule out that volvo. They have a psa 1.6 hdi engine which gives it's fair share of expensive problems. They really have to be maintained extreamly well and even at that there is no gaurantees.
The avensis is the most hasslefree car mentioned in this thread so far along with the prius. A civic and a corolla would be good options too.
Comparing future costs of a Prius to a Lexus GS450h is ridiculous as they are chalk and cheese, plus I thought the GS450h didn't meet taxi vehicle requirements? Also doing mostly short trips a diesel ain't being to be frugal either, a diesel engine takes longer to warm up to optimal efficiency.
administrator - can you please move this to main motors forum where it belongs ?