Well if you have $399.99 Ben's Cycles are willing to sell you "The Ultimate Drivetrain"

Sugino GIGAS 51t
IZUMI Model-V Super Toughness
Euro-Asia Super Cog

Sounds good to me.

I haven't heard that many great things about the Sugino RD, you'd probably be better off shelling out the extra cash for a set of 75s or DuraAce or Miche cranks/chainring