There's a third Ip Man movie that's a prequel, but I haven't seen it and it's not Donnie Yen. I hear it's pretty good, though.
It should also be noted that the new Wong Kar Wai flick, The Grandmasters (which I just posted the new trailer for in the Asian film thread) is also about Ip Man, with Tony Leung in his role.
And I can't help myself but recommend you check out some of Jackie Chan's older movies if you get on a kick of this stuff. They're even better.