Let me start by saying that I do not clean my room before I leave and never intend to. That being said I do constantly tidy up during my stay for two reasons:
1) I, personally, am not a slob and do not want to stay in a mess.
2) I tidy a bit before I leave because it reduces the chances of me leaving posessions behind.
As far as things said in this thread, here are my 2 cents.
1) You could probably clean a 2 bdrm in 30 minutes, but that is one room I would choose not to have.
2) Never expect a housekeeper or anyone to take leftover food, unless it is still sealed in its original packaging. Think about it. You are asking someone to take food from a stranger. Not that I would question the motives of anyone leaving food behind.
I have had the pleasure

of working in housekeeping, though not by choice. I was an accountant in a four star hotel who was pushed into duty during a prolonged strike. Here are some of my observations.
1) When a room was cleaned the computer system was updated through the phone. I would pick up the phone punch in a code and room#. Voila! When the front desk looks up the room it will show as now being cleaned and released inot inventory. Punch the wrong room # and a guest receives a dirty room.
2) I do feel for housekeeping staff as it is not a pleasent job. You would be suprised of some of the meeses. A couple of examples:
A) One room I entered had dozens of beer cans strewn around and a couple packs worth of cigarette butts. The room stank of cigarette smoke like you wouldn't believe. BTW, the room was non-smoking.
B) Another room, I needed some help moving some of the furniture off the balcony and back into the room.
3) Messes aside, they are not that much of a problem. It just takes a bit longer. The only thing that should cause an issue is anything related to damage to the room. Therfore, it is not unreasonable to expect a clean room upon check-in. Regardless of the previous occupants.
Yes, everyonce in awhile you will get a bad room. When you do complain. Not in an unreasonable fashion, but let the front desk staff know. The hotel knows who cleans each room. This info could then be used to spot trends (i.e. issues with specific mousekeepers.)