Meter Garden is influential, I think it's probably the most influential out of all the adaptations. I say that in terms how incredibly popular it was in East Asia and South East Asia at the time. It popularised the story even more.
For Wuxia, it'd always be Jin Yong's. His most popular works is Legend of Condor Heroes I think? Considering how many times it was adapted. You can't really talk about how a specific version influenced dramas though because it's his novels that popularised and influenced the genre. Non Jin Yong well known wuxia dramas are by other well known wuxia writers from same time period.
Xianxia would be Chinese Paladin? which, again isn't the drama influencing other dramas but the original game (1995) creating the genre, and it was adopted and further popularised by web novels, which then got adapted into dramas. The drama is notable for amongst the first (2005) to be aiming for the younger audience. Previously most cdramas were more general audience/family kind of tv.
