Ya know you guys could've just put a "Warning: Spoiler" in the title and saves everyone trouble.
Cowboy Bebop: Grand, just grand. Tragic yes but definently one of the better ways for a main character to go out.
Samurai Champloo: I agree with the previous opinion on this. Unlike Bebop there was no real underlaying storyline (other then the Sunflower Samurai) and thus no need to end on a tragic note. The closure here between the three characters and their realization with one another as they went their separate ways was good enough. Plus who can't love that ending theme that plays over the credits.
FLCL: Somber but I found it interesting since after all the critical-ness of the main character finally slacked up a bit. That and I relished seeing Haru-Haru (or whatever her name is) facing disappointment for once the series.
! Loved this one especially the irony in that after all that, Grave never beared any ill will to his long time bud (and that dude really didn't deserve his forgive-ness.) The final scene is a real heart tugger to me too.
TRIGUN (Manga): TONS better then what the anime gave us, I had a feeling Knives wasn't such a bad dude after all despite his actions. Glad to see the series return to it roots one last time for the final bit.
Death Note: (Manga)
! Contrary to most folks here, I loved Light's endgame. For all his smarts, forward thinking and over confidence. It just took one oversight to undo all he done which I found hilarious (and by a follower of his no less XD). Followed even more by his breakdown reducing him to a desperate shell of his former self. Whew man next to Spike, I thought this was a great end for a character. The anime let Light off too easy.
! If it one thing I hate, its when a series leaves itself unfinished. But to do so in MID-BATTLE? No es beuno. Not cool at all. And that last page? (Shakes head) The anime gave it some closure but was just too generic for my taste. Wasn't the point of the heroes to stop Zeke without killing him thus preventing history to repeat all over again?
R.O.D TV: As much as I loved the series I couldn't help but be unsatisfied by this. Oh sure the heroes win but why is it they never really deal such a bigger blow to the villans after all they put them through outside of saving the world.
Digimon 02: Ugh one can't help but feel the writers ran out of juice and just went with anything. This was a real disappointment to me too cause 02 is my favorite of the franchise. The ending was just total cheese.
Full Metal Alchemist (Anime): After all that and…..what they just end up in another world? =P Well at least Al got his body back, one out of two ain't bad.
Neon Evagalion: One word: WTF?