Yes, on top of wardrobes, under beds (if you can, our bed is practically on the floor!), inside anything! We have a wardrobe about a foot from a corner, and have suitcases stacked up next to it, mostly hidden and out of the way. Also, we got a great couch at Ikea (the best store ever) with storage, and it fits so much in the way of extra linens and pillows, it's great!
That being said, our new rental house has closets in every bedroom, a "Harry Potter" room under the stairs and a...wait for it...double garage! I am never ever moving!