Unless you are a very organized and disciplined person, don't bother with Natural Family Planning. Yes it does work and it works extraordinarily well for some people - people who are METICULOUS about charting their very regular cycles and are in touch with their body's changes at various points in the month (cervical mucus changes, basal body temperature charting, etc.). I'm not knocking NFP by any means, I'm just saying that it is for someone who is willing to be very, very vigilant not to mention someone who can resist temptation or moments of "just this once".
The NuvaRing might possibly be your best bet. It has the same hormones as BCPs without the daily task of remembering to take it. Fold the ring in half, push it in, leave it there for 3 weeks - ta da! Covered for a month and you shouldn't even feel it.
An IUD would also be a good option, but keep in mind that there is a low (very, very low but possible) incidence of potential scar tissue associated with using an IUD. This doesn't happen very often at all, but if you are wanting to have another child you may not wish to take this risk, albeit it very minimal.