No. Virtually all TVs will work after the switchover - even old or black and white televisions - as long as you can connect it to a digital box like a Sky+ box. A SCART lead is the best way to connect your digital box to your TV set. If your TV was manufactured after 1996, it will probably have a SCART socket (it's the rectangular socket with holes for 21 pins). If your TV doesn't have a SCART socket there are still other methods to connect your TV to your digital box - ask your local electrical retailer for the available options.
If you're buying a new TV, look for the 'digital tick' logo. This indicates that the equipment is designed to work after the digital switchover.