Same here. I'd say about 10-15 of my games were bought for over £10. I used to have a fairly large retail PC game collection but that's tiny now - I've replaced most of them with Steam copies. I've calmed down now but I went crazy in Summer 2010, bought about 300 odd games that sale I think!
I used to have my entire Steam Library downloaded to a dedicated 2TB hard drive. That's long since been large enough however...
