Find something you like doing Paul. As people have said...going to the gym is a pretty bad example of 'Healthy Living' cus its generally a bit dull and it puts many people off the whole idea. You may well like it....there are positives...its nice to work yourself in a very structured way, and that appeals to many people, plus theres usually nice chicks to look at! Can always try it though if you think it'll suit you as it does many other people.
For me exercise should be good fun and more than just a calorie burning exercise, therefore you should find something you enjoy doing. Is there a sport you used to play as a kid that you could get back into? Is there something you've always wanted to try? Do you like heading out for walks/out on a bike? Have you got a mate who can plug you straight into a group of people that do something regularly i.e. football, rugby, ultimate frisbee, kayaking, badminton etc? Try these avenues first. Doing something with a bunch of other people will usually ensure you go every week and enjoy it because its social and is in a regular time slot and it won't feel like a chore as the gym can be.
The walking to take some pictures thing is a good one, especially if you like the idea of it. Get the Ipod on and hit the countryside somewhere (or just hit the streets). This is good aswell because you can end up being out for hours which is better than half an hour on a hamster wheel in a gym. Get yourself out there. Also you can always go for a walk at lunchtime for half an hour or so.
Ideally you should be doing something 3 times a week for about an hour. The best way to do that is to have regular days to do stuff and make sure you enjoy it.
Once you've got exercise sorted out, food is your next big thing. You'll have the 3 keys to success going on then. No body pollutants, regular exercise and good diet. Once you start getting pleasure out of these you'll be laughing.