i'm gonna go quite off topic here, hope you don't mind :emb:
well for fighting games (like Street Fighter stuff right?), nothing can replace a good arcade joystick.
i'm happy to have bought the last Interact PC Arcade Pro I have ever seen, and it simply ROCKS for the "versus" and SFA series on CPS2 (and all Street Fighter series before it), not to mention all the arcade games that are meant to be played with a joystick. You might want to look for one of these at eBay or something.
And I also have an Interact Propad 6 gamepad; the original one, not the new ergonomical one.
That particular gamepad has one of the best d-pads on PC controllers. So you might want to check out some of the current Interact gamepads too.
If you can find one, also consider the long-discontinued ThrustMaster Rage 3D and Fusion gamepads. In digital mode, their d-pad is a rather unique design; you move the indented center of the big half-sphere towards the direction (U D L R), instead of pressing down on the d-pad like in conventional gamepads. I find that extremely accurate and swift, more suitable for fighting games than the best of the normal d-pad designs.
And you are correct; analog stick is not good for digital control. That is why they STILL haven't done away the conventional d-pad on the DualShock (ok it's a little weird but still similar) and upcoming Gamecube controller.
(And that's also why my Rage 3D has that digital mode for the half-sphere pad)