I get inspiration from different places:

Cooking shows: sometimes I will just see a dish and go "ooh, I have those ingredients" and decide to make it. There is something about watching someone else make it that can be more inspiring than flicking through a recipe book
Magazines: The new Taste one is looking good so far. Really like the 3 meals using similar ingrediants section. Great way of seeing how versatile some ingredients can be.
Meal plans other have one: Every so often (often for weight loss) I will follow a produce meal plan. Can be very hit and miss with how nice some of the meals are, but great for pulling out of a rut and coming away with a few new dishes.

Like Rouge, can't do full on meal planning any more. We chop and change too much. Had too much wasted food as plans would change (not home to cook meal, not well that night etc). I like to think of one dish I really want to cook, so specifically get those ingredients (good for those meals where is needs to be really fresh), then buy the generic food items that are very versatile. Just seeing what meat is one special at times can get you thinking about different things to cook