Beer Advocate has a great article on Holiday Gifts for Beer Lovers. I like the first three ideas:

Growler Pack
Hit your local brewpub and pick up a fresh growler (or two) of beer. Most places will also sell branded pint glasses, so grab a pair of those, and then ask the bar for some new coasters to go along with them. While you’re at it, why not add a brewpub T-shirt? Then, when everything is ready, arrange your gifts in a metal pail and add some brown packing paper as protective filler. You’re done! To achieve optimum freshness, try to purchase the growler(s) within a day or two of giving the gift, and remember to keep the beer refrigerated.

Glassware Set
Every beer lover needs a complete set of glassware in his or her beer arsenal, so stop by your local Crate & Barrel (or a similar shop) and purchase one of each of the following: flute, goblet, mug, pilsner, pint, snifter, tulip, Weizen and an oversized wine glass. Obviously, there are more pieces available, but these are the basics that should allow the gift receiver to properly enjoy a wide range of beer styles.

Beer and Cheese Pack
Pair a selection of beers with some artisan cheeses. Include some quality crackers, condiments and meats, and consider throwing in a suitable glass for the beers (e.g., a generic tulip glass for a Belgian-style beer).