I actually don't understand why people have such a hard time fitting in exercise. I love exercise! I think perhaps I enjoy it more because I used to be very sick and now I appreciate my body.
I have so many things I like to do that also happen to be great exercise: yoga, biking, swimming, surfing, walking, dancing. If I had more time/money I would also do martial arts and maybe take up rock climbing.
If I had all the money in the world I think I could even do two or more activities per day (with some days off, of course). Already I have some days where I do yoga AND swimming or yoga AND biking.
I think if you can find exercise that you love and isn't a chore, getting into a routine will not be a problem.
I recently started rock climbing and I've been going 2 - 3 times a week for about 3 hours. I still have a gym membership and think about going occasionally, but it's not as fun. As you said, it's very important to find something you enjoy doing and you will make time for it.