Well Phoenix can definitely defeat him. Hulk would be another who can do it. Emma Frost or Professor X could just mentally control him. And stop him from fighting back. I'm pretty sure there's more but that's all I can think of right now.
Um magneto seems to be the only person for a sure kill by riping out the animantium from his body.hulk can't he can wail on wolverine but hed get back up.iron man no iron mans suite isn't made of a strong enough metal to withstand his sharp claws.um captian america could put up a fight with his andimantium and vibrium shield but he can't heal fast enough.um ghost rider maybe with a pentence stare.or doctor strange could find some magic to do it.but I say magneto and rouge sense she can take away his healing powers
hulk, deadpool, magneto (uh, duh), thor might be a pretty good opponent, and... maybe cap? i can't remember if cap beat him or not. cap can push him around a bit, in the least.
Technically, considering Wolverine is just a character in a story, both anyone and no one can beat him. Ultimately it depends on how you chose to write him into a story.
for example, if you wanted you could say Howard the Duck gets his hands on the Cosmic Cube which he uses to take away Wolverine's powers causing Wolverine's healing factor to reject his Adamantium bones , thus killing Wolverine.
