I have always loved renting from VRBO (vacation rentals by owner) because I like having the options of an apartment in a city I am visiting; it makes me feel more like a native when I can shop in the local markets, and hang out in a living room as opposed to a hotel lobby with a constant stream of guests coming in and out.
Roomorama takes the concept of vacation rentals by owner to another venue. It takes the rental concept to rooms in a home or an apartment, like the original idea behind the B&B concept. One of the best benefits is the space for the money; a penthouse loft with floor to ceiling windows near Union Square was going for only $189 a night (about half of what a nice hotel room would cost in the same area).
If you have an apartment or home in a desirable area, you might want to swap through Home Exchange or Intervac, but I like renting without having to worry about someone in my home while I'm away.
Part of the price of a vacation is peace of mind and I don't mind paying that very modest price.