Boris style bikes are generally known as Dutch bikes, a good unisex choice, though some of the more macho blokey types may perceive them as a bit girly with the low stepover frame.
The more blokey type bike would probably be hybrids, flat bar, bigger wheels than mountain bikes, slick tyres, rear rack, ideal for commuting & riding with panniers etc for carrying laptops, work files etc without getting sweaty with a backpack.
Factor in the cost of lights, mudguards (should be standard on Boris type bikes tho) good quality locks etc too.