What are you reasons for wanting to rent out a furnished place?
In my experience, unfurnished is less hassle and the less hassle the better. The properties I own are rented out without appliances (the tenant brings their own) which means I don't have to worry about the maintenance of these appliances.
I think one scenario that would be good for furnished rentals is high end rentals, rented on a weekly basis but there needs to be demand in your area for this kind of thing. Otherwise, there is no point.
Anyway, if you live in the US, Craigslist is a pretty good place for getting furniture at a good price.
Hope that helps.
- jnc