^ What those guys said.
If you want to lose weight, you need to do a lot of cardio AND eat right. Cardio doesn't have to be running, but it has to get your heart rate up and keep it there for an extended period of time. When Sean does a hard weight workout, he definitely sweats it out just as much as I do when I go running or cycling.
In the nice weather, IMO it's easier to lose weight for a couple of reasons. First being that there's more daylight, and more time to get outside and do longer activities. (Runs, rides, whatever). I generally do 5-6 days a week of cardio. My runs are 30 min to an hour, my rides are anywhere from 2 hours to 4-5. The upside is that since I do so much cardio in the summer, my diet consists of Whatever The Fuck I Want, because if I burn 2000 calories before lunchtime, you can bet your ass I'm having a burrito with all the trimmings without any guilt.
In the winter, it's a little tougher but (again IMO) it's all about maintaining. If you're moving less (I do 30 min at the gym 3 days a week, and 3 days of an hour of trainer cycling), you burn less, so you need to consume less calories. That doesn't necessarily mean eat less, but you definitely need to eat better. My winter diet is a lot of tuna on wheat sandwiches, salads and chicken, and I opt for veggies instead of fries, etc, etc. One little bonus for winter is that I have a designated off day - I don't bother with that during the summer, because my summer workouts are things I like to do. In the winter I designate Mondays, and I eat whatever - burrito with a rack of chips, pizza, chinese food, etc etc.
One thing that Sean said in one of the fitness threads (that stuck with me) was basically that once you get into a routine, you start thinking of calories as fuel. Food isn't something that you should dive into when you're bored, and when you're ordering dinner you'll start thinking about what you're about to intake vs what you burned that day. And again IMO, it becomes pretty addictive, and very cool. A 1500 calorie dinner of chicken and veggies will fill you up just as much (and make you feel better/fuller) than a 3000 calorie dinner of loaded meat lover pizza.
The initial hump sucks, but just stick with whatever you think you can actually do a few days a week. I'll never like running, but I like how I feel when I'm done. I love cycling, so I was lucky to find something that is both a great workout and a shitload of fun. But if you can tolerate even 1-2 days a week of short (3-4 mile) runs, you'll probably find that it's not as awful once you start getting in shape, and honestly nothing gets results faster. Running is the fat annihilator man. Run a lot, and you can basically live off of McDonalds and Ding Dongs and still have a six pack.