Yes! I will totally join you. I've been bringing my lunch pretty consistently the last few months, and I'm loving it. Not only is it cheaper and healthier, it saves me miles in my car and it's been making me attempt cooking (not my strong suit). My lunches are much fancier than my dinners now, which adds some fun to the work day. For next week I'm thinking chicken-parm sandwiches and oven-roasted asparagus!
Like thedigitel, I find packing it up helps. I even bring all five lunches in on Sunday (when I swap the car for the bike), so that it's much harder for me to forget and "need" a bought lunch.
(I won't be turning down whatever snacks or lattes my colleagues bring in for me, though ;) for me this is more monetary/learning to cook than a calorie thing)