Even if you're already a member of a gym, it's well worth having some exercise equipment at home. This way you've got all the bases covered, and you'll have no excuse not to exercise.
How many hours a week do you sit watching TV? Those hours can now be put to good use by working out in front of the telly. And how many times have you talked yourself out of going to the gym? On the days you can't get to the gym, you can now work out at home.
Here's some basic fitness equipment I recommend you buy, so you can workout at home any time (if you want personal training in your home gym, check my personal training page):
Yoga Mat (What's the best exercise mat to buy? Get one with plenty of padding to cushion your joints, and make sure it's not slippery)
Swissball (get the right size for you)
Heart Rate Monitor (get the simplest one possible, they're less confusing and less can go wrong with them)
Medicine Ball (medicine ball with handles, also known as double grip medicine balls, enables you to grip better and perform more exercises)
Weights Bench (People ask me what's the best weights bench to buy. I'd recommend a weights bench that has the option of flat/incline at various degrees, as this gives more exercise options)
Dumbbells (buy a range of weights: a pair of 3kg, pair of 5kg, pair of 7.5kg or 8kg, pair of 10kg. For men, also get pair of 12.5kg, and pair of 15kg. Get fixed chrome or rubberised weights, don't get weights you screw bits to add more weight, they're too fiddly and less friendly to handle.)
Pedometers (to measure your total number of walking steps per day - 10,000 steps a day is a good number to aim for)
Massage Balls (enable you to get rid of muscle knots, and boost circulation)
Reaction Balls (oddly shaped balls to bounce and speed reaction time when you catch them)
Wobble Boards (traditional wooden wobble boards, or synthetic variations, great for improving proprioception and balance) - also Slant Boards, Rocker Boards, and Balance Pads.
Exercise Bands and Exercise Tubing (for resistance exercise, a transportable alternative to dumbbells, easy to pack in your suitcase for a hotel bedroom workout or beach workout)
Boxing Gloves and Boxing Pads (great for cardio boxing and kickboxing)
Elliptical Trainers (also known as Nordic Ski, or Crosstrainer, the large cardio machines found in all gyms, now available for home gyms. The best cross-trainers have 20 levels of resistance, and various workout options such as manual, hill etc)
Exercise Bikes (What's the best exercise bike to buy? I'd say get one with different levels of resistance, so you can perform different levels of workout as you progress.)
Treadmills (also known as running machines. What's the best treadmill or running machine to buy? Ideally get one with an incline option)
Abs Wheel (people ask if the abs wheel is safe, and I'd suggest that you need to have a strong core before you attempt the abs wheel, as there is risk of injury if you've got a weak core. It's quite an advanced exercise, but the abs wheel does work if performed correctly.)
Body Fat Monitor (Omron Body Fat Monitors are good - you can get a handheld one - and they use bioelectrical impedence to measure how much body fat you have. A small electric current passes round your body, and the leaner you are, the faster the current passes, as muscle conducts electricity faster than fat. What's the most accurate method to measure body fat? A six or eight point body fat monitor in a lab or hospital would give a more accurate reading than a hand-held device, but that is expensive/impractical for most people.)