Variety! I have a lot of exercise videos that range from yoga, weights, circuit training, old Firm videos, step aerobics, dancy floor aerobics, Zumba... I could go on. I can't afford a gym, so I collect videos. And I like to walk outside.
I also love Jessica Smith's youtube channel: http://www.youtube.com/user/jessicasmithtv She has done commercially produced videos that are great, but her youtube channel is full of great workouts that are all free! She's done strength training, yoga, stretching, walking... a big variety.
I also own and use a treadmill.
And I try to build movement into my day... parking a long way from things, taking the stairs whenever possible, etc.
