Living within walking distance of your everyday needs is like hitting the LA jackpot, but stray from your comfort zone and you'll be stuck buying your Apple Jacks at Sav-On. Don't become a Drugstore Cowboy: check out WalkScore.com.
Based on the nearby resources, Walk Score tells you at a glance whether you can hoof it around the area in question without packing a canteen. Enter the address of your job, your girlfriend's place, or your ex-girlfriend's job, and their proprietary algorithm'll weigh factors including distance to/variety of businesses to return a 1-100 ranking, indicating whether you're checking out a barren wasteland or a veritable Aisle 9 of Walmart. They'll then populate a map dotted with icon-ized establishments: drug stores, dry cleaners, burger joints, walk-in vasectomy clinics, etc -- everything you want, and everything you thought you wanted, until your daily deluge of misspelled unsolicited emails informed you that chicks dig virility.
Of course, Score doesn't take everything into account, leaving out important factors like hilliness, and robbery -- since knowing where in Downtown to get your cereal still won't prevent you from becoming some toothless villain's own LA jackpot.