I started with a bit of Chinese music. "Traditional" Chinese music > Vivian Hsu > Vicki Zhao (Zhao Wei) > Ayumi Hamasaki > Aya Ueto > SPEED > Morning Musume (and most of the Hello! Project sub-groups/solo stuff) > X Japan.
Going from Morning Musume > X Japan is an odd step. If you are wondering how that happened, a friend of mine that I speak to online knew that I listened to "crappy Japanese stuff" as he put it and his friend setup an FTP for him to download some music and he saw a "Japanese Music" folder and said to me "This guy has some of the crappy JP music you like" so I told him to let me see what it is. I logged into the FTP and there were 2 folders. Ayumi Hamasaki and X JAPAN. I knew who Ayumi Hamasaki was so I went into the X Japan folder and it had random mp3s aswell as the "X Japan - Perfect Best" album. I downloaded them all to check it out and the first song I listened to which got me hooked was "Endless Rain". After realising how amazingly awesome X Japan were, I decided to go and try out other Japanese rock bands. And it all went uphill from there. Now I listen to loads of Japanese bands (mostly rock/metal but a few pop artists too) aswell as Korean and Chinese and pretty much any language. I'm more of a music person than a lyrics person which is why I have no problem listening to foreign language music. If the music is good then i'm happy. They can be singing about slaughtering children and animals for all I care.. as long as it has good music playing then i'll listen