We go to Disney every year, so if I don't answer any of your questions fully (or you have more) feel free to PM me for more info.
All of the parks will be fun for you and your hubby. Epcot will probably be the most enjoyable since it always feels the most romantic to me and my hubby. The countries, flowers, fireworks...it just makes for really memorable evenings! Each park has its benefits and cool things to do though. Magic Kingdom has Pirates of the Caribbean, Space Mountain, Splash Mountain, Haunted Mansion, and Big Thunder Railroad as it's "thrill" attractions. Even the "kiddie" stuff is tons of fun thought (who doesn't love It's a Small World?)! Animal Kingdom's safari is one of the neatest experiences and the shows there are really good. Hollywood Studios (used to be MGM) has Tower of Terror, Rockin' Roller Coaster, Star Tours, etc. It's probably the second best park for older kids/adults.
There really aren't any rides that I recommend you pass up. Without kids you should be able to get through the parks fairly quickly especially if you use fast pass (PM me for more info if you need it on that).
As for restaurants...it really depends on what you like to eat. We LOVE eating at the different countries in Epcot. Japan, Morocco, France, and Canada are all REALLY good. We were highly disappointed with Mexico this past year (which is a shame because it used to be quite good). The Coral Reef restaurant is neat, but I have been nothing but disappointed the past few times we have gone there.
There really aren't any great places in the Magic Kingdom, at least none that would blow your socks off and make it worth your while (most are great for kids, but since you will be by yourselves, I wouldn't do it). Close to the Magic Kingdom is the Polynesian Resort. They have an AMAZING dinner at O'Hana. It is similar to a Brazilian steakhouse and will be one of the meals where you feel like you got the most bang for your buck.
Hollywood Studios has Sci-Fi (you sit in a "car" at an old drive in movie theater). The food is decent (American style cuisine) , but the atmosphere is fun. More enjoyable with kids, but it wouldn't be bad without your son. Mama Melrose's is also there. It's pretty decent Italian food and very reasonably priced!
Animal Kingdom is rarely open past 5, so there aren't tons of good dinner places there.
Other places we have really enjoyed are the Cape May Cafe at the Beach Club and the California Grill at the Contemporary. Cape May Cafe is a New England style clam bake buffet, and the California Grill has elegant American cuisine. If you do the California Grill, make a later reservation so you can watch the fireworks go off at the Magic Kingdom while you eat!
Shopping can be done at Downtown Disney or any of the parks. If you are staying on Disney property you are able to send your purchases that you make in the parks directly to your hotel's gift shop. It makes it really convenient to shop throughout the parks without having to carry anything around.
Other than that, enjoy! There is enough to do just within Disney that your 5 days will be packed! Again, feel free to PM me with any questions. I LOVE talking Disney (if you couldn't tell!)!