There's a Recommended Deal every day, as well as a Community Deal, where each offer a bundle of games in one convenient place. Plenty of individual games (more than 600!) are on sale too, plus you can pick one of three special offers each day.
All GOG.com purchases are backed by a new 30-day money back guarantee, so if you buy something you don't like, you can get your money back and use it towards something else. Nice to see another company doing this, and the 30-day guarantee is damned impressive imo.
Plus, you can still get Fallout 1, 2, and Tactics for the low, low cost of zero dollars for a while longer still. The servers at GOG were kind of having issues coping with the demand of that and the Winter Sale, so they had to bring new ones on to help out.