We have no toys in either boys' room which has been fine until now (except T has a few books, stuffed animals, and we let him bring little trinkets to bed ie a truck, his kiddie binoculars, whatever he fancies that night

). I was wondering about this as well though as next year we will be moving them to the same room and I really want it to be their room in all aspects, including having some toys and other things. But I am worried, especially with F being so young still, and the whole sharing room thing being new (it's like they will have each other as toys, lol) that if I put anything in there they would never sleep. So I'm not sure really!
As for rotating toys, I don't really rotate them. We have several boxes, which I try to keep sorted (1 for cars/trucks/other vehicles, 1 for costume/dress up stuff, and 1 big one for everything else) but who am I kidding, everything ends up a jumbled mess. This is where most of the generic plastic toys end up. But I do have a few other boxes which are kept out of sight and brought out when they need a change - 1 with puzzles, 1 with trains and tracks, and 1 with mega blocks. I also go through them regularly and get rid of stuff that doesn't get played with. I do have another stash of toys that are a bit beyond them still (Alphie, which I keep meaning to pull out for T since I think he is getting to a good age for it, and a kiddie laptop that would just get pounded on so I put it away, and something else but I can't remember what it is).