Rowan and I have two trainers and one set of rollers. Both trainers are currently in our dining room, in case we want to use them. I used to ride a bicycle on my trainer a lot through the winter, but since I moved to Australia, it is a rare thing. We can cycle most of the winter. And then this year, we went to Canada right at the end of winter (last 3 weeks of August) ... so we were able to get in a lot of cycling there.

If you can go somewhere warm for a few weeks in winter, take your bicycle and ride. It's a great way to keep in shape in winter.
We have a weight bench and some weights in the garage, and a larger weightlifting machine on the back deck.
We also have several weights around the house which I'll pick up and use once in a while.
I also have some yoga equipment and several exercise DVDs (mostly yoga, but a few others as well).
Most of the time, however, we cycle outside ... and then mix it up with walking (I walk 15-18 km/week year round), and canoeing or kayaking etc. in the spring/summer/autumn. Oh, and I still have snowshoes, but haven't had a chance to use them yet here. If you've got deep enough snow in the winter, snowshoes are a good workout!