I'm a huge jpop/jrock fan. Among my favorite artists are Tackey & Tsubasa, Do As Infinity, Janne Da Arc, Wada Kouji... the list goes on. I also like every Japanese Yugioh/Pokemon/Digimon opening, they are really good at picking songs. Though I don't know Japanese, I tend to understand at least one word in every line, and occasionally full phrases. Of course that doesn't help a whole lot, but in my oppinion, music is about more than just the words. The voice is an instrument itsself, there to deliver the same feelings and emotions that other instruments can deliver. Out of all of them, the voice is the most versatile, it can leave you feeling peppy and happy or in tears. When you have an instrument this powerful, you can manage without understanding the words. However, when it comes to English music, it is nice understanding it, because you can then relate to the lyrics as well. Either way, I like both types and see "you can't understand it" as a poor excuse for not enjoying music from other cultures. =)
On a funny side-note, my dad has said many times that he can't understand the words in songs, only hear the pitch of someone's voice and the instruments. Yet he uses the whole "can't understand it, what's the point" argument on Japanese music. Kind of an irony, huh? :P
