It was actually the Minecraft Lego set that got me back into it last year. They went on sale back in February 2012, at which point I had no Lego (not counting what's sitting in closets at my parents' house from my childhood), and by the time the Minecraft set shipped in June I was already hooked again with their new licensed sets for Lord of the Rings and Marvel. So now I have all the Marvel sets, most of the recent DC line, most of the LotR line, the 4 most recent collectable minifigures sets, and a bunch of other assorted stuff.
I feel a little guilty about just putting together the sets as designed and leaving most of them displayed in the computer room, I'm not taking them apart and getting creative with them, but there's still something awesome about just building them. It's relaxing to queue up some podcasts and spend a few hours clicking those bricks together, and even more so with some of the incredibly complex stuff they have today (the only modular city building I have so far is 10197 Fire Brigade, but it's awesome and I'm planning to get everything else from that line I can find/afford).
So according to the collection calculator at brickset.com I've dropped about $1,800 on Lego in the last year or so. Yikes.