I still get pissed off every time I think of the finale.

For the books:
It takes place about a month after Dexter's Final Cut, an awful excuse of a book that was random sex scenes for the sake of it. Dexter actually feels something for another human too, a rather out of character situation even with the attempts at humanising him in Dexter is Delicious. When the woman he's cheating on Rita with is murdered as well as his wife, Dexter takes the fall for it. The irony wasn't lost on me, but the writing was bad enough I was surprised he would be charged with the murders.

This horrible writing carries on into Dexter is Dead, the final book in the series. You probably know that in the books, Brian isn't killed in the first book. He returns in this one with a powerful lawyer to spring out Dexter from jail, and Brian explains that his skills have allowed him to thrive in the drug trade. Back to that shortly. Deborah tries to make Dexter give up custody of his kids to her, and in the end she decides to let him keep his kids. I'd like to say there was more to it than that, but there's very little time devoted to this, and it would have been better to flesh this out.

Through a series of other bumbling events (Brian's ignorance that credit cards can be hacked, two gang members killing each other trying to kill Brian,) people try to kill Dexter and Brian, and it's discovered that their lawyer is the one who's decided to sell them out to gang members. It's a fairly obvious twist, but it's not made very clear why he does this. It's suggested he was offered more money, but it's a glossed over theory. As well as this, Dexter's kids are kidnapped by this gang, and Dexter comes clean with Deborah about how Brian is still alive, and they intend on hatching a plan to get their kids back. Brian and Dexter torture a guy for information and learn of a yacht where they're being held. They storm the yacht, Deborah gets away with the kids and Brian and Dexter die.

Ignoring the rather bad writing, here's a list of plots that are never revisited:
Doakes - He's something of a cyborg by the 3rd book, but he was hunting Dexter right up until Double Dexter.
Chutsky - Deborah's boyfriend, and father to her son. Never seen again after Dexter is Delicious.
No followup, afterstory or anything. Sure, it's told from a first person perspective, but it literally ends at Dexter's death. There's no further characterisation of anyone else in the series, most of whom are still 1 dimensional even after 8 books.

I...drink...your...MILKSHAKE!

I DRINK IT UP!!!