Saiyuki

(clicky on image for awesome lightbox effects)
L->R: Gojyo, Hakkai, Goku, Sanzo. There's a four leaf clover next to Sanzo.

Summary from mangaupdates

Having been assigned by the human elders the mission of stopping a mystical plague that has afflicted the Youkai with madness, Genjyo Sanzo assembles his team of Youkai warriors, desperately hoping that the disease will not affect them. He sets up qualifying tests that will help him determine the loyalty and worth of Cho Hakkai, Son Goku and Sha Gojyo. The team then journeys west to rid the land of madness.

Goes from Saiyuki Ibun (pre-prequel, story of Sanzo's master) to Saiyuki Gaiden (prequel, story of the party's preincarnations) to Saiyuki (main story) to Saiyuki Reload and Reload Blast (title change from change of publishers). All are very loosely based on 西游记 (Journey to the West).

*random insert* Sanzo is ranked 2nd after Icarus <3

Seeing the rate of update, I'll probably never get to read the ending. So here's my own version (aka spoilers and skip down to image):
First off they accomplish their objective of stopping the resurrection, then beating the crap out of Ukoku Sanzo (he's really creepy, but kinda cool in his own way). But before he dies, he uses his power of denying existence (really awesome power, I'd like to have plz.) to destroy the castle. Sanzo & party tries to escape, but is killed off one by one. This becomes a repeat of their escape from heaven in Gaiden. Goku realizes, turns to true form, saves everyone's dead bodies, regain memory etc. Kanzeon Bosatsu (she looks really manly...) feels really guilty cause all this happened again, somehow bargains/threatens (cause that's much more like her) the emperor of heaven and the souls of Sanzo, Hakkai and Gojyo returns to being Gods in heaven, in turn regaining their memory. Goku & Nataku are friends again. Last page would have 2 panels, top one shows Sanzo telling Goku something like "see, we kept our promise", bottom panel would be all of them enjoying the cherry blossom at the place Goku promised to show Nataku. Big happy ending :]


(click for fullview)

Isn't Goku adorable? *u* Moderately editted by moi and is looking beautiful as my wallpaper.
Scan (and the first 2 images) from Salty Dog V and IV respectively. Gotta love 'em artbooks.