My most played is Ridge Racer 2 on the Viva Nonno emulator.
No idea why. I can run the same track for a friggin' hour in that game trying to place first, and I don't get bored.
(BTW, it works flawlessly in MAME now if you have the horsepower)
Second most played is Crazy Taxi, although the music drops out after a couple songs and Demul is a PITA to set up.
I have the PC version with the crappy music replaced by the original arcade music, but it just doesn't feel the same.
It's a fun game to play while drinking...if you do such things.

Honorable mentions: Sega Rally Championship, Scud Race, Outrun 2006 (PC)
With proper shifter support, I've been enjoying the older sprite based games like Outrun & WEC Lemans.
Chase Bombers is a lesser known gem once you get the hang of aiming the weapons.
(choosing automatic transmission doesn't make much difference in that one)
EDIT: I'd actually put Model 2 emulator higher on the priority list than MAME when it comes to an analogue wheel.
(Daytona USA, Sega Rally, Indy 500, Super GT, Manx TT, MotoRaid,
Sega Touring Car (they can't all be winners)
EDIT AGAIN: Virtua Racing on MAME! There is something about the look and engine sound that just feels right.