The DVC resorts are Old Key West, The Boardwalk Villas, the Villas at Wilderness Lodge, the Beach Club Villas, Saratoga Spings Resort, Vero Beach Resort and Hilton head Island Resort. You can also use points at any Disney resort (except for the value ones) as well as the cruise line.
Are you renting a reservation from a member or purchasing your own DVC points, either from Disney or through a resale agent?
If you are renting a reservation, you get the best bank for your buck by staying at a DVC resort.
If you are buying your own points (good until 2042 or 2054, depending on the resort), you still get the best bank for your buck at DVC resorts, but there are places all over the world where you can use them.
The rental prices generally run $10-12 per point (this price includes tax, and there are no additional fees). The number of points required depends on when you go and which nights you stay. With DVC, Friday and Saturday nights are about double the cost of Sunday-Thursday, so the specific nights you'll stay make a big difference.
Figure out your dates, then click on the "DVC Point Charts" link at the top of the page and calculate the number of points you will need.
For additional info on renting DVC reservations, go to the DIS DVC Rent/Trade Board. First read the FAQ, and then read the other "stickies" at the top of the page. If you have additional questions on renting, come back here and ask.