Been married for two years and absolutely love it...
But then again...my wife is super hot, intelligent, and and really spunky/creative...so we have a lot of fun.
I think they are several keys to marriage...this is just my opinion:
Selflessness - gota live for one another and make the choice to live that way every single day
Religion - I think having a moral religious focus in your realtionship is very important, if not a religion then I think you need to at least have a shared vision to pursue.
Time - gotta spend quality time together, my wife and I don't even own a TV because it wastes time.
Low Stress and Rest - Stay outta debt (lots of stress in this one) and don't slave away at the office...in the immortal scheme the things, it will not matter whether you drove a Civic or a 325is. Live within your means and save money in Mutual Fund for the future/retirement. It is actually fun and even addicting to watch your savings grow...from 1,000 to 5k to 10k to 25k to 50k to 80k and so on...
Stay physically fit - can't stress this one enough...sexual attraction really is important in marriage. I'd still love my wife regardless of her weight or looks (at this point, maybe not when we first met). But the fact that she is a hotty is such a big plus...coming home from work is always the best part of my day...except for bedtime. Same goes for me...I've maintained my 31" waist and will continue to lift weights to increase my muscular size and fitness. I'm naturally on the skinny side so it's been a real chore but I'm up to 190-195lbs @ 8-10% body fat (I'm about 6'1-6'2".
Also, being physically fit has many other effects: you get more respect, get paid better, promoted faster, have more energy, etc.
I think if your missing a few of the above components, then marriage will suck.