More important - diet or exercise??

Absolutely diet. When I first started working out I was about 195 lbs. I worked out three days a week from May-August and my weight went up during that time to 199. It wasn't until I started counting calories that the weight started falling off. I think exercise plays a really big role in keeping weight off once you've lost it, though. I maintained about a 50 lb. weight loss, not watching calories, but exercising vigorously six days a week and I didn't gain the weight back. Programs like Weight Watchers are pretty successful and as far as I know you can do the program without exercising at all. You have more wiggle room if you do exercise, but you can still lose without it.

My first reaction was to say "EXERCISE!" but after I thought about it, it's diet. I was out of town this past weekend and got really off of my normal diet/exercise schedule because of the hectic nature of my trip. I came back home and had so much to catch up on, that I haven't really gotten back to my "norm", though I've been trying to workout where I can. I've only worked out a couple of times in the last week (I usually work out 2x a day, 6 days a week), and gained 3 lbs when I wasn't watching my diet but lost them back when I started counting again. I think exercise has been helping a lot, and I need both for me to feel successful, but diet definitely has the bigger impact for me.

It is different for everyone, but as a broad generalization, proper nutrition (as always, I hesitate to use the word "diet," as that implies something temporary) is more effective for weight loss.

One can do 1,000 crunches a day, but never have 6-pack abs if they're scarfing on pepperoni pizzas and cheeseburgers every week.