Caliban, why did I know you were going to bring up the GSP?
Anyway, any of the premium ISSF standard pistols such as the Walther GSP, Hammerli 208 or SP20, Unique DES96U, Pardini SP, Britarms MkIII, etc, are going to be so close in bench accuracy that it would require a scanning electron microscope to tell them apart.
For more combat-oriented guns, the Heckler & Koch P7, SIG P210, and any number of custom bullseye 1911s are duking it out over that title.
Later,
Chris