I'm surprised you don't do YouTube often. I'm practically hooked on it. From being shocked by seeing Boogie Woogie #5 on LinkTV's World Music show 5/6 years ago to now virtually knowing the history of Japanese rock, I'm doing pretty good and I have to thank YouTube for that. Just last night I pulled up the videos of Yuki on PaPaPaPaPuffy and then went and listened to Judy and Mary videos. One could see the reverence for Yuki that Ami and Yumi have for her and then one can listen to the music and know WHY they worship her!!
And now I'm on this huge Ai Kago kick.....................there are so many Aibon fans who have posted vids of her or made OPVs that I can indulge my fascination of her to the point of neglecting the things I SHOULD be doing! 
Well, I used to scour YouTube much more often than I do now, which is only once in a while. A big reason for cutting down is what you mention -- I could spend days there listening to stuff (I have a similar problem with Wikipedia, where I'll just keep following links to new articles for hours on end). A bigger reason, though, is my slightly obsessive nature; if I hear something really good then I'd want to go and buy tons of stuff because I like to physically
have the CD in my collection...which I don't necessarily have the money for. And if I
really get into a band, then my obsessive completist nature sets in and I want to collect as much as I can (because half the time there are awesome album cuts you just can't get on compilations or singles). With Japanese artists this can be bad for a couple of reasons: one, the CDs are expensive, and two, Japanese musicians release music at a breakneck pace compared to American acts -- very much like English-language artists in the '60s did. It's not so bad with my favorite '60s bands, because most of them don't record new music any more (except the Stones), but it's a different animal with Japanese rock acts (especially considering they release 2-3 singles a year to boot, and many of
those have exclusive tracks). I shudder to think if I ever heard anything by, say, Yumi Matsutoya that I liked -- she's released some 30-odd albums, not even counting compliations! (Granted, she's more an exception, but still.)
I'm a big YUKI fan, too. I picked up her remaining albums I'd been missing just last month -- I could give you some recommendations if you're not overly familiar with her stuff. I also have
Miracle Diving by Judy and Mary (picked it up for $7 used at a store nearby); it's good, but I think I like solo YUKI better.
And I've mentioned it on here before, but I'm kinda creeped out by the entire Hello! Project. Though I do recall seeing a couple of clips with (I think) W and Morning Musume singing with Pink Lady (whose best of album I own, and is kind of a guilty pleasure for me), and it wasn't bad...if you can get past the underage girls dressed in tiny outfits.