I've written many times about my love of Logitech Harmony remotes. And here's one of the best deals I've seen yet: CompUSA has the Harmony 520 (refurbished) for $39.99.
Ground shipping will run you about $8 (unless you spend another $60, in which case you qualify for $1.99 shipping on your entire order).
The Harmony remotes are renowned for offering (relatively) easy programming via desktop software, which is available for both Windows and Mac systems.
Just choose your home-theater hardware from an extensive (and frequently updated) database, then set up your desired activities ("Watch a movie," "Listen to music," and so on).
The remote's built-in help screens walk you through any problems that may crop up (like the TV turns on but the receiver doesn't), great for when grandparents, babysitters, and other non-residents are trying to operate your stuff.
The 520 is definitely an entry-level model, meaning it lacks rechargeable batteries and has a monochrome, not color, display. Even so, it definitely beats juggling all your remotes. CNET liked it well enough at $100, so you can't go wrong at $40.
Oh, and don't worry about this being a refurb: It comes with a full one-year warranty from Logitech--same as new units.