P-Model are amazing.
Polysics, P-Model, Spoozys, Metronome, etc. That whole scene is amazing.
My favorite "Japanese" band is NUMBER GIRL. Anything related to them: TODDLE, ZAZEN BOYS, SLOTH LOVE CHUNKS, VOLA AND THE ORIENTAL MACHINE. Just mindblowing.
SHIT THAT ROCKS AND IS ESSENTIAL!:
blam honey [one of the weirdest bands I've ever heard; if Nine Inch Nails were good and made by someone who hates music or something -- brilliant!]
bleachmobile [also known as Bleach'03; AMAZING]
bloodthirsty butchers [their early stuff sounds like Fugazi]
coaltar of the deepers [careful; one of their albums is J-Pop, one is J-Pop death metal, and the rest explore shoegaze or kraut rock -- very eclectic band]
gaji [like a Japanese Jesus Lizard obsessed with harmonics -- essential!]
limited express (has gone?)
luminous orange
number girl [one of my all time favorite bands; they're my user icon...]
ogre you asshole
super junky monkey
toddle
vola & the oriental machine
SHIT THAT ROCKS BUT ISN'T ESSENTIAL:
9mm parabellum bullet
art-school
bandwagon
boom boom satellites
bugy craxone
nico touches the walls
the pillows [not a huge fan, but lots of people are, so..]
plastic tree [early stuff]
red bacteria vacuum
sloth love chunks
sparta locals [sound like At the Drive-In]
SHIT THAT KINDA ROCKS AND IS KINDA ARTY:
brilliant green
ex-girl
fujifabric
mo'some tonebender
quruli
SHIT THAT'S BLEEPY, BOUNCY, ETC BUT PROBABLY, UH, "ROCKS"!:
cali-gari
metronome
polysics
spoozys
supercar [early stuff]
REALLY FUCKING GREAT J-POP:
capsule
coltemonikha
electric tomato
mac monald duck eclair
motocompo
pena
plus-tech squeezebox [craziest band EVER; like Mr. Bungle doing J-Pop]
POST-ROCK/MATH ROCK TYPE SHIT:
mono
world's end girlfriend
zazen boys [essential!]
AVANT-GARDE/FOLK/NOISE TYPE STUFF:
all boredoms related bands
abe kaoru
aki onda
ami yoshida
angel in heavy syrup
aube
brain police
broomdusters
c.c.c.c.
captain trip
chie mukai
chu ishikawa [does the music for Tsukamoto films -- great stuff!]
ché-shizu
contagious orgasm
cornelius
doping panda
dowser
dumb type
flower travellin' band
fushitsusha
gerogerigegege
ghost [I guess they're fairly well known now, but...]
go hirano
high rise
hijokaidan
hiroaki mizutani
hiroshi nar
hiroshi shiotani
hoppy kamiyama
ikue mori [was the drummer of DNA; "Hex Kitchen" is ESSENTIAL!]
kazuki tomokawa [acid folk singer; one of my all time favorite musicians, if you care...]
k.k. null
keiji haino [duh?]
kozo inada
lsd march [excellent; one of my favorite bands as well]
mainliner
marble sheep
masami tada
merzbow
michiyo yagi
minor coffee shop
musica transonic
naoki zushi
novo tono
nobukazu takemura [another artist who varies in range quite a bit; I prefer his more ambient stuff]
otomo yoshihide
overhang party
oz disc
phew
pinakotheca
reiko kudo
ryoji ikeda
sachiko m.
sawako
seiji nagai
taj mahal travellers
tenko
tetsuo furudate
tokyo kid brothers
tokyo rockers
toshimaru nakamura
tujiko noriko
violent onsen geisha
white heaven
yamazaki maso
yoshida tatsuya
yoshizawa motoharu
zero gravity
Like I said, favorite recent band is Yolz in the Sky. Enjoy.