My favorite ace is probably Hermann Graf...his aircraft were quite pretty, red tulip nose, white tails, and a neat saw-tooth splinter pattern on the wings.
All of their stories are incredible, regardless of what country they flew for...but, here's my list of favorite aces' aircraft...yeah, most are overdone by us modelers, but they're still pretty aircraft.
Graf's 109 and 190 - Red Tulip nose, white tail, sawtooth splinter
Hartmann's 109s - Black tulip nose.
Lander's Big Beautiful Doll P-51D
Tarheel Hal - P-47D
Dave Schilling's P-47D in RAF camo colors
Mac McKennon's P-51D 'Ridge Runner III'
any of the 352nd FG P-51s
There's a few more...Macchi 202s and 205s are pretty aircraft, and some of the La-5s and La-7s, Yak 3s and Yak 9s, have been painted up pretty dramatically.
My two cents,
Jeff