Headlong for me. Probably the best asymmetric FPS map I've ever played. 1-flag/bomb worked perfectly on this map(just about everything did, actually), and it was always my go-to spitscreen map when buds were over.
Honorable mention goes to Lockout, The Pit, BloodGulch, and Terminal.
I can't decide. But the maps I like are probably maps no one else did, I liked the big BTB maps like Containment and Waterworks. --- I do not aim with my eye, I aim with my hand. I do not shoot with my hand, I shoot with my mind. I do not kill with my gun, I kill with my heart.