One Book

[BritishSeaPower]

1. Federation
2. Doctor's Orders
3. Immortal Coil
4. Avatar
5. Full Circle (I haven't read it yet, but having read the Golden Post-Series books, if someone really wanted to read Voyager that's where I'd tell them to start.)
6. "The Legend of Porthos"

 

[Admiral Rex]

Great question!

A. Destiny Book 1
B. Crucible: McCoy
C. Imzadi or Vendetta
D. Millennium Book 1
E. Full Circle
F. The Good That Men Do

 

[JD]

A: Destiny
B: Spock's World
C: The Buried Age
D: Avatar bk1
E: Full Circle
F: The Good That Men Do.

 

[Thrawn]

Keeping in mind that if you can only give someone one book, something standalone is better than the first book in a continuing series:

Well, but, I'm trying to get them into TrekLit, right? The idea is to give a friend a book that will make them say "that was good and I want more books like that". And there's a bunch of first-of-a-series books in TrekLit that do that really well.

 

[Paris]

I pretty much agree with SCI:

A: Articles of the Federation / A Singular Destiny both by KRAD (tie)
B: Spock's World by Diane Duane
C: Destiny Omnibus by David Mack
D: Plagues of Night/Raise the Dawn by DRGIII
E: Full Circle by Kirsten Beyer
F: The Good That Men Do by Martin & Mangels.

I'm not really a fan of Enterprise, but I thought that TGTMD was the best of the bunch that I read. As for Voyager, I'd also try to push Unworthy and Children of The Storm. That relaunch is amazing