All the time.
LOTR/Muppets/McFarlane stuff and more probably. But I just buy what I like for the most part.
LOTR is pretty much the same for me. Two problems though: I want a full set of ringwraiths and I dislike Hobbits. So I have too many wraiths and no hobbits. I know that's foolish, especially with respect to the hobbits, rather central characters for the story. But yeah, size is an issue and not just for women.
Muppets are not so bad, other than that they don't get released up here. Mostly these are for my wife, but she has no space in her office at work for them, so not much left to pick up. She has a regular kermit, Gonzo, Waldorf and Statler (thanks Scott) and an adventure Kermit. Cool figures, but I don't need them so much.
McFarlane is forever messing with my mind. Sportspicks is the worst, but I own every Predator figure too outside of the 12" line. Not sure why I do either? I like them, thought the movies were entertaining (haven't seen AvP) but I'm not sure I need these guys.
As far as sportspicks goes, I am liquidating a big chunk of that collection right now. The hunt and absurd price for the 3rd Jersey Patrick Roy figure killed my complete goalie collection, so why bother having a bunch of guys I don't care about? I'll still get players I want and like, but it will end up going from nearly 100 figures down to about 20 or so. Still love my Selanne figures though. Dropped my Brodeur today and bent the peg though

Fell right off the shelf, bounced of the filing cabinet, CPU, desk, bin, floor. Thud. The re-release of Vikings figures is nice for me. I'm not so keen on being a completeist at all there, so since I have a spiffy brand new purple Pepper I'll likely sell off my series 1 version.
Simpsons are done, but I've always been pretty controlled in that area. I love the Homers, just waiting for Scott's package to be done with them. Only a few figures aside from the Homers that I own - the THOH figs that came with the sets to get the Homers; Burns x3, and then a few figures that I curse Scott out for every time I look at them.

Hot Wheels are sadly tempting. Some look like crap, but lots are really cool looking and there is a huge bout of nostalgia for me when I see them. Plus they are so very cheap to buy. I kept three of my vintage hot wheels but sold off the rest for a tidy sum. Still I am well controlled here, only buying the batmobiles (sold off my vintage batmobiles as well) and the occasional car or treasure hunt when I see them.
Marvel Legends I've always been pretty good with, though I'm questioning why I bought a brown Woverine

I don't need more of these. Chase figures irritate perpetually and still think about selling most of them. Spiderman Legends are great, but I'm holding out for the box set to be clearanced at Amazon just like the X-men box was. I hope I don't screw that up.
My biggest problem is picking up stuff and then not trading it. So very much crap in my office, notably sportspick variants no one wants but I just can't leave them on the shelf

Overall, under control, except for all things star wars.