Yoko Shimomura for her brilliant arrange album "drammatica",
e.g. http://www.youtube.com/watch?v=aqqMSKDDNJU or http://www.youtube.com/watch?v=x6HpkYcTjqY
and for lots of other great compositions such as http://www.youtube.com/watch?v=pQcZbQ6UEew
She's my favourite VGM composer at the moment.
Masami Ueda/Hiroshi Yamaguchi/Rei Kondoh for Okami,
e.g. http://www.youtube.com/watch?v=y0CbB-G9MXY (Kondoh) or http://www.youtube.com/watch?v=_XPsYCyZlGs (Ueda)
Hitoshi Sakimoto and his 7 colleagues for Oboromuramasa,
e.g. http://www.youtube.com/watch?v=RwllSL46Grg (Sakimoto)
Takahito Eguchi & Noriko Matsueda for my favourite VGM Piano collection - Final Fantasy X-2,
e.g. http://www.youtube.com/watch?v=L6MBv-4ocT4 and http://www.youtube.com/watch?v=K4xRCCz5ZWM&feature=related
Naoki Kodaka for Albert Odyssey Gaiden,
e.g. http://www.youtube.com/watch?v=O7wIu0aDk5Q and http://www.youtube.com/watch?v=n-SFIEhoKT0
Kentaro Haneda for his Wizardry compositions,
e.g. http://www.youtube.com/watch?v=UKQQjfgCmEM and http://www.youtube.com/watch?v=fNCi0ccAddA
Hiroki Kikuta for Seiken Densetsu,
e.g. http://www.youtube.com/watch?v=b2tniOMDPLs or http://www.youtube.com/watch?v=zaaIBwlFG5U
Shunsuke Tsuchiya for his contributions to Arc Rise Fantasia (his compositions on this OST are better than Mitsuda's and Shimomura's),
e.g.http://www.youtube.com/watch?v=0yE6pIB2eGg or http://www.youtube.com/watch?v=xdaUfIUXV4U
Masato Koda for his brilliant Monster Hunter Main Theme http://www.youtube.com/watch?v=D5kUdEpqewE
Yasunori Mitsuda of course for Chrono Trigger (I'm currently discovering his Xeno works) and more recently for his wonderful Soma Bringer tunes,
e.g. http://www.youtube.com/watch?v=vl-0ymKTtlI or http://www.youtube.com/watch?v=lWUWxOoCKZc or http://www.youtube.com/watch?v=H64pW_jKQYs
Yoko Kanno for her work on Nobunaga's Ambition and Uncharted Waters,
e.g. http://www.youtube.com/watch?v=ETqCEGBowHA or http://www.youtube.com/watch?v=nsreFA5KjYE
Michiru Yamane & Yasuhiro Ichihashi - whoever of those two composed the following fantastic tune for Castlevania-Order of Ecclesia:
http://www.youtube.com/watch?v=bPiQm6-K2kM
Ko Otani for Shadow of the Collossus. I'm not convinced of the OST as a whole, but I love
http://www.youtube.com/watch?v=qR_s3BGLu0s
Kondo & colleagues for Zelda, Uematsu and colleagues for FF.
Lots of more to discover and import from otaku.com, my search for great music will never end... 
Sorry for all those direct links, but my 2 machines (PC/MAC) and 3 browsers seem to be cursed whenever I enter VGC. I can't embed any links.
