Pillow Cases & Sheets: We spend approximately 1/3 of our lives in bed, so you want to make sure it's a clean place you actually want to be. Your sheets and pillow cases can collect bacteria, dust mites, lint, sweat, and dirt (especially if you don't shower at night), so wash them weekly.
Purses & Wallets: Tests have shown that purses and wallets carry unwanted germs (just think about how many random floors you've set that purse down on, or where the cash in your wallet has been), and to avoid getting them in your system, you should wipe down these accessories with baby wipes (or, for cotton, use a standard washing machine) about once a week.
Microwave and Refrigerator: Once a week, you should take everything out of the refrigerator and wipe down the inside with a mixture of water and white vinegar. This will also give you a regular opportunity to check the expiration dates on all of your food. Wipe down any food spills inside of the microwave, as well as the keypad on the outside.
Computers & Electronics: Even if you regularly wash your hands, your computer, keyboard, mouse, and phone are exposed to tons of bacteria all day long. Use disinfectant wipes to gently clean electronics; if you're using anything harsher, make sure everything is unplugged or turned off.
Sponges: Yes, you have to clean the things you use to clean things. Sponges are a hotbed for germs, and since you use them to wipe other surfaces, it's easy to spread the bacteria around. Throw them in the microwave on high for 30 sec, and replace them every couple of weeks.