I hear ya, Scrubking. =) TRUST ME!! I love being a host when friends come over ever since I was in Jr. High and like to make sure they're completely comfortable. I'm not a neat freak, but I keep things in my rooms very neat and orderly. I'm not a messy person to say the least. They also know that I'm a collector of many things, not the least of which includes video games.
Again, I want to make sure they're completely comfortable, but I'd hope that they'd have enough respect for how clean I keep my house. So, when I try to ask in as nice a way possible that ppl wash their hands before picking up a controller, especially when they're eating Cheetos or something, there's very little fuss. Sometimes, however, some ppl just don't care or forget seeing as they never do that at their place. Thankfully, my other friends will point it out to them quite quickly so I don't have to seem like an ass. ^^;
In any event, when I go to other ppl's places and use their controllers... man, it's just nasty how greasy and slimy those friggin' things are. But it's there place so what can you do besides crackin' a few jokes at how nasty their controllers feel. =) Truth be told - you come over my place, you won't have to worry 'bout that!
-Soujirou