All Depends on your budget, and what you race on. Being that you currently use a DFGT, it is safe to assume either PS3 or PC.
For roughly +-$250, you can get a Logitech G27. It has an h-pattern shifter & clutch pedal.
For slightly more, you can get a Fanatec GT3RS Value pack for $300 after shipping that includes a load-cell brake pedal, and 2 shifters(1 Sequential, 1 H-Pattern) that attache via poles or shifter adapter.
Then if you have more $$$$ to spend, you can get either a Thrustmaster T500RS(does NOT come with shifter, you can purchase the TH8RS for +-$130 more) for +-$500. OR, you can look into the Fanatec ClubSport Wheel. That with Pedals & shifter are +-$900-1,000.
It is a matter of preference from the T500 to CSW. Some like the sharp steering characteristics of the T500 over the smooth of the CSW, or vice-versa. I hope this helps you out!