Depending on several factors, these look like fun to me:
-Isamu Alva Dyson (Macross Plus)
-Ozma Lee (Macross Frontier)
-Heero Yuy (Mobile Suit Gundam Wing)
-Sousuke Sagara (Full Metal Panic!)
-Ikki Tenryou + Metabee (Medabots) (Yeah, I liked it, bite me
)
-Batou (Ghost in the Shell)
And more,
just listed a couple of robot-related candidates for now