A million comments and viewpoints, so I couldn't help throwing mine into the mix. While not an adherent of the Hackers Diet per se, it articulates the same principles that I beleive.
I've lost 80lbs in the six months from May to October this year, from 320 down to 240. I anticipate being around 200lbs by January 1. I limit my calorie intake and endeavour to avoid too much fatty food, do weight circuits three times a week, aerobics (elliptical and cycle) 5-6 times a week and, VERY IMPORTANT, dance salsa
Calorie control works. If you can't measure it, you can't control it. If you don't track it (I use an iPhone app) you can't measure it.
The time in the gym is mainly about maintaining metabolism and preventing muscle loss. The calories burned give you some headroom in keeping under your intake limits as a secondary benefit.
Find a supplemantary activity you can *enjoy* that is going to contribute to your goals. I personally hate the gym.
When I say Salsa, I'm really menaing a lifestle change - for me that is Salsa. Salsa classes are as effective as an aerobics class (and far more entertaining). Meanwhile, in an evening out dancing, I can burn through anything up to 800 or 1,000 calories (polar heart monitor based readings). At a minimum I'm far ahead, even if I have a couple of drinks, and your metabolism is cranked for a good portion of the night. Worst case, I can grab a slice on the way home and not feel particularly guilty about it. Compared to sitting at the bar boozing, or sitting on the couch at home, enough said.
Salsa might not be what works for you, but finding something that is entertaining while being beneficial makes it far easier to acheive your goals, and goes along way to maintaining the results once you've acheived them.
In these matters the only certainty is that there is nothing certain. -- Pliny the Elder