I hate leaving things in hotels... I remember once when I was a kid we stayed in some crappy hotel for a week and I left £1 ontop of my table, when I got back it was gone... The maid had stolen it and I was sooooo upset. But yeah, you should never leave anything valuable at all in your hotels. You never know whos gonna walk in and find it.
I usually hide my valuables deep in my luggage but all of these stories have made me pretty paranoid!
For the most part, i try to avoid leaving valuables ANYWHERE that is not on me. But if it cant be helped, it cant be helped I guess. Things can be stolen anywhere, even out of your hands. As for the dirty beds and things, very little things gross me out, so I really dont mind that sort of stuff at all. I dont even think about it. X)
I don't like leaving my stuff in hotel rooms, but it can't really be avoided if you want to get out and enjoy your vacation properly! I just hide my stuff, and try to make sure I hide it REALLY well! sometimes I use those safes they occasoinally have in the hotel rooms too, but even those make me nervous about leaving things behind.