As far as the US goes, I'd never rent a car in NY or DC. Public transportation is good, traffic is maddening and parking is scarce. But in almost every other city I still rent cars quite often. I like rental cars because of the flexibility, boot space for storing my bag before check-in/after check-out and not having to worry about aggressive cab drivers and the like. The only part which annoys me is refilling the tank when I'm done... If only California still let hybrids in the HOV lanes I'd pay extra and rent a Prius at SFO and LAX every time.