I often see discussion about JRPGs and WRPGs. But nobody ever is clear about what makes the difference between the two. So please explain it to me: what makes the difference between JRPGs and WRPGs? Is it only the country of origin (in that case make statements like 'I like JRPGs over WRPGs' completely no sense) or is it about the gameplay? And if it is about gameplay, what are the defining differences?

To make it even more clear, you might classify the following games into one category or the other:
Rogue ( http://en.wikipedia.org/wiki/Rogue_(video_game) )
Nethack ( http://en.wikipedia.org/wiki/Nethack )
pedit5 (probably the first computer-RPG: http://en.wikipedia.org/wiki/Pedit5 )
Final Fantasy
Pokemon
Fire Emblem
Battle for Wesnoth( http://wesnoth.org/ )
Crimson Shroud
Denpa Men
Diablo
Heroes of Ruin
Tales of ...
Dragon Quest
Wizardry
Ultima
MUDs ( http://en.wikipedia.org/wiki/MUD )
World of Warcraft
Dragon Crystal
Etrian Odyssey
Baldur's Gate
Skyrim
Dragon Age

JRPG - Men look like women.

WRPG - Women look like men.

hahaha...

that's actually somewhat true.... -___-

Huge eyes?

Rare exception. You've obviously never played Oblivion. (dat ugliness)

lol its entirely about country, jrpgs can be made to feel like a wrpg and vice versa. however most of the games from Japan have japanese themes, ideals and preference in gameplay or storytelling, the same goes with western games. thisis why saying you prefer 1 to the other makes sence. something like this could easily be compared to racing sim vs arcade racer if it wasnt for the countries their made in.

WRPG remember their penn & paper role playing roots. 

JRPG is all about the developers wanting to tell a story and coming up with new "unique" battle systems that nobody asked for.

WRPGs are more likely action based

This one really confuses me a bit sometimes. Western RPG's have become quite different in the sense that you get to play the role you want. I feel the eastern ones are more like action adventure games with turn based combat and well in some rare cases action too. I say this not having played many games known as JRPG's but i will give it a try. What i mean is that meaning of role playing is quite different in both sub genres.

WRPG- Weaker story, Character customization, you choose how the character develops. Combat is single-action based. Usually single person. Less "fantasy" more mediveal/Sci-fi. A health bar. Lots of Guns. Side quests.

JRPG- Hair color, plot twists. You're given a cast of characters and you can choose your main if you wish. Combat is multi-action, requiring combo strings and many things happening at once. Battles are over the top. Numbers randomly floating out of enemies. Swords, Swords, Swords. More Linearity.