Rotary ones e.g. Philishave aren't bad. Foil type ones like Braun cut a little closer but don't work on anything but short stubble so are a bit crap really. I'm not convinced all this floaty-head thing makes a big difference, but Philips are usually a good bet.
I would buy one, but make sure it is easy to change, and say once he has opened it, that you did some research, but if it isn't the one he likes to use, you are happy for him to change it. Cash to me is a bit of a cop out. I would rather have something to open, that showed they tried, rather than just receive cash from the other half. Just my opinion though.
Thank you all - DH is clueless as to which to get, with the proviso that he wouldn't buy the make he's got again. I bravely said I would do the research and surprise him! The Braun foil sounds like a good bet though.