Just a quick one to gauge some opinion

Am considering getting a bike via cyclesheme for commuting to and from work. It's 16 miles each way with a couple of stiff hills, and can at times be very windy. Already got a carbon road (and a fuel full sus) bike but prefer not to ride it in winter and too nice to commute ever day (and fancy a new bike)

So options are:

Singlespeed road bike with flip flop hub (not sure on hilly terrain?)
Cyclocross bike then can ride on and off road and can double up for short blasts when the full sus is overkill
Hardtail or rigid mtb with discs and run two sets of wheels (slicks/nobblies) for commute/mtbing

Anyone any thoughts as to what is the best/most usable option – can't decide what the option to go for is.

Cheers for the help