I always enjoy Sugimori artwork very much. The pokemon are best when they are drawn by Ken Sugimori, I think. This is to post special things Sugimori made, it don't have to be pokemon. With special, I mean work that not had been made public, such as lost promote art, or wallpapers.
I have a few examples here.
Shiny Charizard wallpaper, which includes Gold/Kenta/Jimmy.
G/S Neo Expedition TCG expansion.
TCG Neo 3 promotion
Jirachi, also includes May and Wally.
Red/Green/Blue starters art.
Mystery Dungeon Blue
Mystery Dungeon Red
I would like to see more, so if you have art like this, you can share it with us here. You can also discuss about the posted art, of course.
This link contains a zip with most Sugimori art, and was made by CowDude, who also posted some awesome stuff here.
*Credits to all of the members who posted art here, especially CowDude and Bulbatordile for some of the examples and Murkronos for almost all the renders*
The zip was newly edited on October 19, 2007.