I think it's better to stick to the basics when it comes to genre's
I can deal with having these basic genre's
Pop
Rock/Punk (These two genre's seem to cross-over so much recently)
Metal
RnB
Hip Hop
Techno/Electronica
Rap
Jazz
Soul
Classical
etc etc
In fact there are quite a few genre's that I'm glad are around
I think it starts getting silly when people start using these delightful little genre's
Deathcore
Grindcore
(In fact every single sub-genre of metal effectively annoys me to no end)
Screamo
Post-Hardcore
Indie Rock
Indie Pop
(NB especially annoying if the artist is not actually independant at all)
And so many other sub-genres..... I just looked at all of the sub-genre's for Indie Rock..... MY GOD WHY ARE SO MANY
It all just sounds the same anyway
To me Sub-genre's are just the fan's way of trying to make their favourite artist seem more unique than another fan's favourite artist.... even if both artists sound the seem.
The ONLY time sub-genre's or cross-genre's (Ex. when an artist takes the fundamentals of two or more genre's and combines them, for instance Pop-Rock) is when you actually can't simply label the artist as one thing
For Instance
I can't label Koda Kumi as simply a J-Pop artist.... because she does so much more than J-Pop
She breaks the boundaries between Pop, Rock, Techno and RnB/Hip-Hop
If you look at this:
Ningyo Hime PV
and then look at this:
Under PV
and then at this:
Wonderland PV
and try to tell me that she's not breaking boundaries there
But ONLY with artists like that is it acceptable
[NB.... wow that was a bit of a rant]