I've been attempting to simplify some of my daily and weekly chores, and as I mentioned in an earlier post, that includes planning ahead for grocery-shopping trips. I use a notepad similar to this one (Thanks, Em!) to plan out the weekly menu, and I add the ingredients to the grocery list at the same time. You can find this one here. (Obviously you could do the same thing with your own notebook or pad of paper. Martha Stewart would tell you to make your own notebook out of paper that's only been used on one side, but we don't all have time to be Martha.)
For inspiration, I have a recipe box of old-standbys, I keep a binder with recipes from Cooking Light or Bon Appetit, and I have a number of cookbooks that have earmarked pages. I also enjoy looking online, particularly when I have a specific ingredient I'd like to use. (Cooking Light - My Recipe, Epicurious, or even Real Simple or Martha Stewart, are often used.)
20-30 minutes over the weekend is all it usually takes to plan it out. It is so nice not to have to think about what to do for dinner every night. I also make sure to plan for leftovers - they can take the stress out of a particularly busy day or make a good lunch that I can bring to work.
*Here's another example of a pad - this one is perforated between the menu and list, which allows you to take the list with you to the store while keeping your menu in your kitchen!