To those of you who don't know what to pick up, what's integral, etc...
I like to pretend it's all integral. Even though I am the ULTIMATE sucker when it comes to falling for marketing tricks, I'm the kind of continuity nut who likes to put everything in order and read it over again.
If you want some "essential" reading, however...that is, stuff that gets mentioned later...you might want to look into the S.C.E. books that tie in to DS9's relaunch. The very first story,
Cold Fusion, is pretty integral and flows right from
Avatar to
Section 31.
Aftermath isn't really referenced, but
Malefictorum, Lost Time and
Wounds all feature DS9 characters. I'd also recommend checking out Kira's first visit to the Captain's Table.
Other things that aren't very integral at all, but still worthy DS9 tales in their own right: The
N-Vector comics and the
Divided We Fall comics,
A Stitch In Timeand
The Lives of Dax.
Stuff that contains cameos/stuff that's not nearly as important:
Diplomatic Implausibility mentions DS9 through Worf, who is acting as the Klingon ambassador. He gets a message from Dax and replies to it.
Maximum Warp actually takes place prior to
Avatar, with cameos of Jast and other members of the crew. They were doing
something for 3 months, after all!
What can I say? I'm nuts about this stuff. But I also hate being limited in my post-series material. There's still more out there that I haven't read, and it makes me happy

. I actually haven't read a couple of those S.C.E. stories or
The Final Artifact...but I'm hunting them down!
I like a series that accounts for every moment that goes by, and shows the organic nature of life, and how every event affects everything that follows it. So yeah...three months go by before things get interesting with those characters and locales again? Nuts to that.
So uh...that's all for now. Peace.