I think it's easy to get "stuck-in-a-rut" when it comes to cooking, which makes it boring. I think it's good at least once a month, to stick your neck out there and try something completely different, it may even help to mix up your cooking style a little.
I have a ton of cookbooks, and I love them, I wouldn't mind if I ended up with a whole bookshelf of them eventually! But, one thing I've noticed about cookbooks is that they're usually very safe and basic. My new favorite addiction lately has been cooking magazines. I LOVE them, they're usually a little cheaper (but be careful, I learned the hard way that some of them can still cost around $10), and they have recipes in them that are a little more "daring," or just a little less conventional. I have really found some winner recipes in magazines I've bought.
My favorites are Cooking Light, Taste of Home, and Weight Watchers. They all have really fun, fairly simple, and of course, lighter calorie recipes in them.
Another thing I love is that since you get them month-to-month, you can find more seasonal recipes. Right now, most of the magazines are dedicated to grilling and BBQ-ing, so I've gotten tons of ideas.