2010 gave us a very nice set of releases from GW. The long awaited Blood Angels and even longer awaiting Dark Eldar. There had even been rumors that the Dark Eldar were going the way of the Dodo. Thankfully not only are they back, but with more fanfare than ever could of been imagined for what was considered a rare sight to see army.
Looking forward into the next year, I am very excited for what is on the horizon. GW has put out for 5th edition extremely high quality codex's. Codex creep like the old days is gone, and instead you simply have to adjust for new army types that are hitting the shelves. 2011 should really be exciting. I am hoping that GW can re-create the hype it saw in 2010. It should look like this for 2011.
April/May: Grey Knights
Summer; "Summer of Flyers" 7 large flyer kits. 2 Dark Eldar, 1 tyranids, 1 space marines/blood angels/grey knights, 1 Tau, +?
November/December: Sisters of Battle
Remember the large grain of salt. This all comes from various sources and even if this was penciled in on GW's calendar, it may not hold. The first two are the most likely, Grey Knights and Necrons. It is possible for Sister's to be replaced with Black Templar, however rumors suggest otherwise. This would be a lot of codex's this year if it holds true. Tau would be the likely candidate for something beyond Sisters of Battle after the beginning of 2012.