Every once in a while I'll see one of these things in my condo:
They're pretty fast and creepy and my gut reaction when seeing one is, "Holy smokes! What the heck is that?!??! Ick! Kill it!", but from what I've read, these little critters are actually beneficial. They're called house centipedes and according to those in the know, they've come to the US all the way from Europe. It just wouldn't be kind of me to kill them after they've travelled so far. What kind of welcome would that be? "Hi, welcome to the US. Meet the bottom of my shoe. I hope you like it." No, no, that just wouldn't be right.
They are predators (as are spiders) and they eat all sorts of "bad" bugs. So, I figure, if these things are managing to survive in my condo, there must be a healthy diet of bugs that I just don't see around. As long as they don't start biting me (which supposedly they are capable of doing), I suppose I won't start squashing them, either... even if they are awfully ugly creepy