The only wheel on the market that can fully utilize the higher resolution FFB in GT5, or any game for that matter, is the T500. The high end Fanatec wheels are still using a Logitech emulator. Simple, the best wheel for the current gen of "consoles" is the T500. There are far more expensive and better built wheels that are only compatible with PC sims.
I liked each of my wheels, each has improvements over the one below it. Fortunately, it comes down to budget. If you can spend a little, get the DFGT, absolutely the best budget wheel! Fanatec wheels can do things that Logitech wheels can't, which gives them the edge in the middle price point.
I also own the HKS controller, really frustrating. The full range of gas and break "pedals" only use about 1/3 of the total throw. Ugh