One bike, one gear. It's all I ever need.
No ambition.
I have ended up with an 06 enduro as my winter bike and a 2012 enduro as my summer bike...keeps me happy 
I have a spare bike which I use more in the winter. Similar to the main bike but with cheaper (and heavier) bits. Both full suspension, same length cranks and near identical riding positions.
Winter bike? Er, yes, I suppose so......
Road - Alu C'dale Synapse with mudguards.
Every eventuality bike - 1998 Marin Pine Mountain with Exotic carbon forks. Was a god send in the snow.
My road bike is about to become my winter road bike. On account of a summer road bike arriving soon 😀
I have a GT Avalanche which I got last February as a 'winter bike' to save the wear and tear on my FS bearings... but as it has been like winter most of the last year I've done much more riding on it than I expected.
