Naked in Death is definitely an A+. It's interesting to see how much Nora has developed the characters and the series throughout all the books. Still, this one very much stands alone.
I have a confession to make: after reading this one and Rapture, I like the Eve of the first books much better than the one from the later ones. She's much more tolerant and is sometimes even nice. She doesn't rip people's heads off for asking "how may I help you". I still like the latest books, but I think I like these much better.
Roarke hasn't changed all that much. He's now much more developed as a character, but he hasn't fundamentally changed.
The plot itself... ok, but, as always, not the most important element of the book. What I did see much more of is world building. Nora goes into much more detail about 21st century history here than in most of the rest of the series (maybe except Loyalty). This was very enjoyable.