My dad used to travel 300 days a year on business, and the best advice he ever gave me is this: if you're going to be in a hotel for a few days or more, on the day after your first night--in other words, when the maids clean up the room for the first time--you leave a decent sized tip. $5 will do the trick, though if you can afford it go for $10. Along with this, leave a simple--but special--request: extra towels, extra glasses, or whatever. You'll not only get enough towels to open your own car wash, but for the rest of your stay your room will be immaculate and if you have any special needs they'll get taken care of. After that leave a buck or two a day and when you leave another good sized tip--particularly if you stay at the hotel regularly or plan on coming back. If you're doing anything sleazy in your room it also buys the silence of the housekeeping staff--my dad also used to say that a properly tipped maid could find a corpse in the bed and she'd just move it so she could remake the bed and fluff the pillows...
Obviously if your idea of proper accomodations is a Motel 6 by the Interstate this probably won't work, but if you're higher up on the food chain a small toke for the help will be one of the best investments you'll ever make. A well placed tip is one of the best lubricants you'll find to ease your way through the hassles of day-to-day life...