Best scene? Either Gin vs Ichigo or Aizen vs Urahara, Isshin and Yoruichi. The former because Gin subverted the shonen law of explaining all your abilities in great detail to the opponent you're using them against by blatantly lying, not just to Ichigo but even Aizen. Keeping the true ability of your Bankai secret for decades from your own boss is crazy. The latter because we got to see a few characters fight that we hadn't seen in action yet. That Kido combo of Urahara's, the little joke about Yoruichi's leg, Isshin flicking Aizen away, that epic moment where Aizen said he'd let them hit him with everything they had just so he could crush their hopes one at a time... That entire fight was on a different level to the normal battles in Bleach, least of all because it was one of the very rare times a fight was between more than two people and had actual teamwork involved.