Effective/ Ineffective Conclusions

The last novel I read was Brisingr. I thought that the conclusion was very effective because it ties all the events of the whole series together very nicely. I really like it when authors leave you hanging and thinking What's going to happen next? and then everything is explained in the next book. I know from talking with friends, that many people DO NOT like it when the author leaves you hanging, because they just want to figure out [for example] "Who killed that man?" and they just want to find out in that book. It was also a good conclusion because it really gave the characters perspective of the situation (which I like).