Full ending, that a never a second season will come for the anime are
Gungrave-extremely fitting closure, and the end, end's it all
Gilgamesh-The show also has an ending that ends it all, but don't know if you will be able to like the ending.
Basilisk- Another ending that ends it all, and never will you see the same characters again.
gundam 08 ms team- Very good and complete ending in my opinion
Blue gender- ending is a little rushed, but I enjoyed the ending alot, and it was complete.
X tv
Rahxephon-Has a very good, and fitting ending, that I really enjoyed watching.
info can be found at
www.animenewsnetwork.com/encyclopedia
Don't know if you are looking for an ending, where they will never have a second season for it, or an just a good happy ending. The recommendations I have given you have both of them, except some don't got the "happy ending," You still can enjoy the show.