Good topic, especially since most anime that I have seen lack this type of ending with lots of good closure, which is what I prefer over ones that are just completely open-ended. I mean, don't get me wrong, I love to have some certain things left open and unanswered so that even when a show is done, I can still think about it some more in terms of its ending, but I really dislike it when a lot of the great anime that I watch have endings which just lack a feeling of any sort of major accomplishments having been made at the end, or that don't give me any real sense of complete-ness. With that said, these 3 anime just off the top of my head come to mine as great anime with good endings that actually make them feel complete:
Cowboy Bebop- Its got a good bit of everything that I love to see in a good ending, and that's all that I will say about it, on the off-chance that there is actually someone here who STILL has yet to see this show in all of its glory. I mean, I'm pretty sure that everybody here on the anime board would have already seen it, but I don't want to spoil it for the few who may not have. I will say that the ending has always made me feel sad, but while its bitter, it also has a sweet spot to it, that really makes it feel satisfying, and truly completes this excellent series, overall.
Yu Yu Hakusho- While I would have enjoyed the final arc more had it not been so rushed, I still liked what I saw, overall, and I definitely loved the final episode, since its an actual ending. Just about everything that I cared about in the series got a good sense of closure to it, and this is probably one of the few shounen anime adaptations from a manga that ran for over 100 episodes and managed to cover the whole entire story with barely any filler episodes to go along with it, at all.
Death Note- Once again, I won't spoil it for anyone who has yet to see it, but what I will say is that I know that I'm probably alone on this one. Most people hate the ending and the overall second half of the series for Death Note, but it always really appealed to me, and the ending was just so satisfying. Not only did it bring the series to a definite close, making it feel complete, but while it was a very predictable ending, it ended EXACTLY the way I had hoped for it to end, and I really can't say that I was displeased with the results of everything, as they turned out in the end of the series. Of course, I wasn't surprised by them either, and that's surprising considering that this is a series full of surprises.
Still, sometimes a predictable ending is good, and for me, the ending to Death Note is clear proof of that, since I was really enjoying everything I read/saw. I remeraber that as I read it for the first time in the manga, I simply couldn't take my eyes away from the pages, and was completely glued to the series for the last 10 or so chapters. Well, I was addicted to the series from the beginning, but the final 10 chapters just had me going on non-stop, which was a lot of reading for me in terms of Death Note, since each chapter in that manga series is usually full of text and takes longer for me to read than most chapters of other weekly Shounen Jump series, especially since I analyze this series a lot more than I do with any other Shounen Jump title. As for the anime, while it changed the ending from the manga quite a bit, I really appreciated the more emotional approach that they gave it, and it also struck me as a really well put-together conclusion to the series. The fact that both endings kept me excited the whole time, and really struck me as truly memorable, is all the criteria that I need to call them fantastic endings, in my book.