I've already written about my personal cookbook (or, more accurately, both of them), and the portable file folders I use to store recipes I want to try.
What I didn't mention was the rest of my menu planning method.
Our weekly menu follows a rough plan - Sundays I generally cook something that provides leftovers. Often it's in the crockpot. Now that the weather is cooler, we'll have soup once a week, often on Wednesday. Friday is always an easy easy meal (or it's leftovers) because by the end of the work week I'm TIRED. I try to only have one meal a week that's beef-heavy, and aim for one if not two vegetarian nights. I usually only plan 5 nights worth of meals because we'll have sandwiches or go out or scrounge something other nights.
Oh, and I try to always check the weather forecast; if it's going to be really cold and drizzly one day, that day becomes a prime candidate for soup, etc. I also scan my calendar at the same time to make sure I remember if we've got anything coming up that will have an impact on our dinner plans. Last week, for instance, L had a work event Thursday night so wasn't home for dinner. I certainly don't want to plan a favorite of his if he won't even be around to enjoy it!
So, with all that in mind, when I start figuring out our menu for the week, I first look in the file folders to see what sounds good. I'll usually pick 3 new recipes a week, then go to my personal cookbook and fill in the other two from tried-and-true favorites.
This all sounds much more complicated than it really ends up being; I can usually plan a week's menu in 15 minutes, and create a shopping list from it in only 5 minutes or so after that.
A recent addition to my planning is adding the menu plan to my Google calendar; this way I can be at work and easily remind myself of what's on the agenda for that night or later in the week. I used to hand-write it on a calendar in my planner, but I find I prefer the Google calendar because I can easily move things around when we change the plan. And since there hasn't been a single week that we've followed the plan exactly, this is a huge plus. The electronic calendar has also let me find recipes on websites or blogs and just link to the page - I've got some ideas planned ahead that I found during blog reading and internet surfing.