Exactly right. I'm 5'10", and was tipping the scales around 225lbs with a diet and lifestyle like the submitter. Here's what worked for me:
1. Ditched high calorie drinks (soda/juices) and limited snacking. Mornings, I switched to eating a single bowl of cheerios or two shredded wheat biscuits or a banana. Lunch is simple, sandwich, less than 400 cal. Dinner--I rarely eat out, and eating at home I have stopped eating dessert and eat smaller portions at dinner, with no second helpings.
2. Exercise. I run M/W/F for 60 minutes in the morning before work. Tu/Th, I do weigh training (pull ups, push ups, sit ups, other simple stuff), which takes me about 45 minutes. Google Evil Cyber's beginner workout if you want details.
In three months, I've dropped to 207lbs. I'd probably be lighter if I could break myself of *#!*$"&!! cookies, but one needs to be reasonable. My hope is to be below 200 by the end of May, and down to 190 by the end of the summer. You pretty much just have to build on your success, and if you fall off the horse by missing a few days in a row, get back on as soon as you can...but don't beat yourself up about it.