If you're looking into hormonal birth control methods, I would recommend Implanon. It's similar to the depo-provera shot, with not as many bad effects.
My wife used depo-provera for 2 years, and a few months ago we decided to switch off of it because it's supposed to cause bone density problems if used long-term. Side-effects for her were weight gain (15 pounds
over 2 years, at the beginning of which she had knee surgery, and wasn't able to be physically active for months) and loss of period. It can be risky to use depo though, once you get the shot, it's basically a mega-dose of progesteron that will stay in your body for 3-6 months. Once you've got it, if you have bad side-effects, you're stuck.
Implanon uses progesteron too. Implanon is a tiny implant that gets put into your arm via a needle, they numb your arm before putting it in, and it will ache a bit for the next couple days. However it will work for 3 years before you need to take it out. Additionally, if you have any bad side-effects, or decide that you want to get pregnant again, you can have the doctor remove it. The progesteron will be completely gone from your system and you'd be fertile again within a week. With depo, if you decide you want to get pregnant, it could take over a year after you've used it for a year. My wife hasn't had any big change in side-effects since having the Implanon put in, occasionally she had an abnormal amount of moodiness for the first two weeks as she adjusted, but it didn't last long. (and I deserved it anyways :o) )
The difference with Implanon is daily micro-doses vs tri-monthly mega-doses with depo. Trials rated it at 99.9% effective too, out of 1,000 women, not one got pregnant :)
Good luck with your decision, if you decide to consider Implanon, be sure to do your research first.