Nujabes... oh man where to begin!!!
I was lucky to go on a trip to Japan in 2005 and it was some heads on this very forum that I heard recommend Nujabes. I managed to pick up a few releases while there; Hyde Out First Collection, Nujabes' first album Metaphorical Music and the Pase Rock album Bullsh!t As Usual. Also the two Samurai Champloo soundtracks.
After that I pretty much picked up every album Hyde Out released until Nujabes' sad passing. A lot I got from HMV Japan (they had a good website and decent shipping rates - I also got Thes One Live at the Rootdown Soundclash through them and the Double K Ssence compilation). Others from juno.co.uk who imported some, or a japanese friend or two. I must have spent a lot on all that shipping over the years!
So I got all these close to when they came out (these are all on CD);
Nujabes - Modal Soul
Modal Soul Classics
Hyde Out Second Collection
Jemapur - Dok Springs * personal favourite *
Uyama Hiroto - A Son of the Sun & Freedom of the Sun
Emancipator - Soon It Will Be Cold Enough
Modal Soul Classics II
Kenmochi Hidefumi - Falliccia
Substantial - To This Union a Son was Born
I also got Nujabes "third album" Spiritual State that was released after his death. But it is a lot of unfinished tracks so it's not the same. Some are good but some maybe should have stayed in the vaults. I haven't really bothered with any of the other posthumous stuff, endless tribute albums or Shing02 reissues.
I have a few 12"s but not so many. They are hard to find!

Somewhere I also have the Uyama Hiroto - Waltz for Life will Born 12" and the DSK remix 12" (both awesome) and Nujabes 'From The Ground Up' remix (not that great actually).
But my most treasured ones are actually not Nujabes productions but are from his Tribe record label (there was also a Tribe shop in Shibuya). These 7"s are just beautiful music;
FK (dude worked in the shop and has beautiful productions. I've never seen anything else by him).
Seietsu (album is available on itunes. It's good very chopped beats but these tracks are the best)
Coffee & Cigarettes Band (nice version of jazz standards)
Taninaka (dope heavy jazzy beats)
Thirdiq (full album is also great but this has a nice FK remix on it)