Unlike m_eiman and cemerick, I regard dumping debris into my Downloads folder as a feature. I basically never clean it out; it's just a convenience place to keep stuff that I have a low probability of ever wanting again, auto-sorted by how likely I am to want it (most recent first, in other words). Since I almost never bother with more than the first few items in the stack display of Downloads, it didn't occur to me that cleaning it out might be a chore, or even desirable.