By all accounts, 2009 was the Year of the Megadungeon.
I think that a strong case can be made for 2009 and megadungeons, as evidenced by the existence of Dungeon-a-day (whether or not you agree that it is a true megadungeon), Megadungeon.net, and the numerous blog posts and forum discussions regarding the topic all over the internet. Being a fairly simple guy, I like things that are big and have always liked megadungeons. Obviously, many other people do as well. On the one hand, I am disappointed that I came so late to the OSR party. By the time I found it, the year was mostly over, and megadungeons seem to have been supplanted somewhat in the online discourse. I will say, however, that we are working on a megedungeon product: A set of maps (what else?) that presents an ancient dwarven city--a BIG dwarven city. The intention is for it to be similar to Locales, Volume One in that it will not include fully-detailed, fully-statted descriptions of its contents, but only brief descriptions of the major areas. The maps themselves will also include a good many notes (in true megadungeon fashion) so that they are useful to the DM.
According to many people in the blogosphere, 2010 is going to be the Year of Science Fantasy. If that is the case then that is exciting as well, as we are also at work on a product, a supplement as it were, written to expand the horizons of one of the retro-clones toward sci-fi. More details to follow.