A lot of the guys mentioned played(and retired) before I started 2 1/2 years ago, but since then(and in no particular order)....
Klink: War Sears, we can't ever have a server where he doesn't blow me up at least once, it's become a tradition. Even when I kill him, I come out of it shaking and sweating.
Dogmatix
Lords Krueg and Saxon
Rommie: The entire SPQR(I prefer to stay on the Klink border when possible)
Benbean
Walleye(he gives me fits in any race's ship)
Kzinti: Chuut Ritt
Matsukasi
Cougar
Bruce: Kroma
GWarlock
ISC: anybody in a CCZ
Lyran: Moggy
Wendigo
FireSoul
Hydran: I honestly can't remember ever flying against a regular in PvP on a server. If I'm wrong, I'm sure Deadman, 762, Bear or Max will remind me.
Fed: I've rarely flown against these guys, but for a wingman in a serious PvP, these would be my first choices:
Jeff, Die Hard, Thrain, Aussie, Tracey, Sparty, or Hondo.
If it's just for fun, and especially if there's a humorous element:
Jeff, C-Los, Hondo, KRolling, SirX, and whenever he flies Fed, Mav.