If you skip to like 2:40 you'll see Ryomou make her entrance. She then proceeds to perform one of my most favourite moves in anime history:
She does this move once more versus a dude in the first series, and at the beginning of the 2nd series she performs it on a female. Unfortunately, from that point onwards she gets beaten more and more often, which is a real shame because when she's winning she is totally awesome.
Magical Witch Punie-chan is also a very tough grappler. You wouldn't think to look at a 'loli' like her that she'd use that style but oh yes she does for sure:
During one of the full-length episodes she also performs a highly imaginative submission move on a gigantic demon, I'll find it and post later.
Videogame wise my favourites are the street fighter girls (Chun Li, Cammy, Sakura, Makoto etc), Tina Armstrong from DoA and Blaze from Streets of Rage 2! The best vids are when you see very skilled players dominating in match-play using those characters. Back in the Capcom vs Snk 2 days, there was a period of time when people found new tactics with sakura that made her nearly unstoppable (countless videos of a ratio 1 sakura beating the hell out of ratio 2 sagat). Chun Li was also very dominant back in the 3rd Strike days. I'll see if I can find some vids but for now...