My friend showed me this band a while back
I don't listen to J-Rock or J-Pop alot, but this bands songs are phenominal
I have two here:
Supercar - Strobolights

Supercar - Wonderword

This is one I found myself and have taken a liking too
This is about all I listen to of J-Pop/J-Rock:
Polysics - Electric Surfin Go Go!