Choose a place with a lot of variety. La Cava in Epcot is lovely, but if it turns out you don't like tequila, there's not much to drink. Likewise, Trader Sams is great fun, and if you can get there sometime during your trip, you should- but all but two of the drinks are rum based, I think.
A nice dinner at the California Grill with its light (but tasty) cocktails, a fancy dinner, and Wishes sounds great to me. Later in the week (or maybe earlier in the day), both Epcot and Downtown are fantastic.
Downtown in particular, Raglan Road has a ton of imported beer, an okay wine list, scotch and Irish whiskey flights, then a good list of cocktails using small batch bitters and the like. Plus good food and loud music with pretty gals and handsome guys dancing.
The hanger bar is new and has a diverse list of cocktails, but the inside is very tiny; get there early. Morimoto's sake selection and intersting cocktail have become a new favorite of mine; probably only after Bluezoo in my 'neat cocktail' spots.
Really, though, anywhere you go you'll probably have fun. Try not too mix too much hard liquor, drink the hard stuff before wine and beer, and drink plenty of water. I'm a bit jealous- have a blast!