The type of exercise you do all depends on you and what you like to do. What you hate doing, paying membership fees, and whether or not to buy equipment are all things you need to consider as well as answer.
If you choose something that you don't like to do, you aren't going to keep doing it for a long period of time. Give it some thought - if you don't like jogging, you aren't going to get up at 6 AM and go running. If you can't find something you like to do, choose something you hate the least, which will normally be walking.
Walking is great exercise, as it suits all levels of fitness. Anyone can start a walking program at any time, it's normally the intensity and duration that differs. Walking is also a social exercise, as it isn't difficult to find a training partner to chat with while you exercise. Walking with a partner will also make time go by faster.
No matter what exercise you choose, you should start at a low level of intensity and build it up over a period of weeks, which is essential to the longevity of your exercise program. If you start off too hard, you could end up with an injury which will require time off to get over.
If you are really in bad shape, you should start off by walking for 10 minutes each day. Then, increase it by 5 minutes every 2 weeks. To make things more interesting, you should try walking a different course every few days. You can also roster a different friend to walk with you each day of the week.
If walking isn't your thing, then you may want to try a fitness center. They have loads of variety and normally have trainers on hand to answer any questions you may have. When you choose a fitness center, make sure that they give good service.
If they aren't willing to treat you well before you join, then they certainly won't after you join. You should also make sure that the equipment they use is well taken care of. It's easy to find out, as all you have to do is listen to the machines. If they squeak a lot or make noise, then chances are they aren't being taken care of. If you still aren't sure what you should do, then you should look into golf or tennis. Both are good social activities in most areas, and you can even meet new friends. Tennis is great for fitness although it isn't for someone who is just starting out. If you haven't exercised in a long time, then golf may be the best activity for you.