Room service: I tip anywhere from $2-$5 a day. I don't leave a mess.

Bellman: almost never use this service. Actually, I came into this thread because in the last two places I stayed, both Marriotts, they actually charged me to bring luggage up to a meeting room or guest room. At one Marriott, I shipped a piece of luggage to the hotel. When I went to receive it (I had tracking on it, so I knew exactly when it was there), I was told that the hotel's policy is to charge the guest $30 per item. I asked if I can be waived the fee since (1) the hotel did not inform me of this fee when I called to ask; and (2) I could transport the luggage to the convention meeting room myself. The bellman didn't budge on this, so I just let it go, and let him walk the piece of luggage to the meeting room, while I held onto my hand cart uselessly. I didn't tip because I figured it was part of the $30 service charge.

The second instance happened when I arrived at the hotel with two pieces of luggage and a box. I asked the Bellman to borrow the luggage cart. He came and I told him I could port my own luggage to my room. The Bellman said that that was not hotel policy, that he would have to do it for me. Additionally, there is a $4/item service fee. I was not informed of this, so, annoyed, I told him I will haul all my luggage up myself without the cart (it's doable, but very unwieldy, and will take me 3x as long).

Parking valet: I don't use the valet at hotels, but at restaurants, I generally tip $2.