What type of exercise you do is less important than doing something. You can claim that optimality of the exercise contributes to motivation, but this seems like a common failure mode. People spend more time researching optimal exercise than doing anything.
The best way to get motivated for me is to quantify the health benefits. A generic "it's good for me" is not motivating. A specific percent reduction in risk of a CVD event is.
When my dad was a boy, the idea of a gym (outside a school gym) was fairly unknown here. They were like, want to get stronger? Go kayaking. Want to lose weight? Play soccer.
With Alicorn's permission, I'm resurrecting this thread.
I'll start off with one of my own: What kinds of exercise can I do at home (I do have 5- and 20-pound weights), and what are good ways to get motivation to do so regularly?