What sort of strategies do people receommend with Greyjoy? I'm trying build an intimidate/stealth deck centered around military & power challenges with a ship sub-theme.

What chapter packs contain good Greyjoy content?

you hit a lot of their themes. they also have unopposed, deck discard, winter, and saves.

as for chapter packs with what you want look at

Clash of Arms Packs for: Seawater Scalawags, First Mate, Longship "Foamdrinker", and Fishwhiskers

and in the recent packs (defenders of the north): Nute the barber and Naval escort.

there are a lot of solid utility characters in the other chapter packs cycles, like island refugee, alyans greyjoy, Distinguished Boatswain, and scurvy

A good way to start with greyjoy in lcg is to build an aggro deck based on winter and military crest. To be effetive I recommend you a lot of characters (34-36), the most of them should cost 3 or less.

For the plots I go for Blockade, Fear of Winter, 2 or 3 more plots of claim 2, Fury of the Kraken and Time of Ravens. This is a good start for the plot deck.

There are many other kind of lists, but this one is easy to build and run and it's quite effective.

Thanks guys, I'll try to post a deck list after our gaming club get's our next round of chapter packs.