Stormonu
NeoGrognard
Same for me here. In Ravenloft it'd be curse you don't want to hang around, possibly involving Dark Gifts and a slide for control by the DM.For me, it's setting dependent. If I'm doing Ravenloft, it's something where I'll be looking at rules that also treat the affliction as being a curse so the Monster Manual might work there. But for a regular fantasy game, I really like Eberron's Shifter species.
For my own main homebrew though, I'd start with the Shifter race (or Lycans, as they're called in mine - they actually have their own homeland) with feats at higher level to become more like a specific lycanthrope. However, in my world lycanthropy is a "gift" from the Beastlands, and there is a lot of teetering between the mentality of a beast vs. the mind of a sapient being. A lot of lycans eventually go mad and devolve into killing monsters* that have to be put down. PCs are generally exceptions, but the threat of losing one's mind always lingers in the background.
*(Kind of like Ghouls from Fallout)