by Starhawk77
Depends what you're looking for. If you care about the game's overarching story, then you should buy the packs in the order in which they were released. Each pack adds another chapter to the narrative, so it won't really make sense if you purchase them out of order.If you just want the most powerful cards, then the latter half of the Dwarrowdelf cycle is a good place to start (especially Foundations of Stone/Shadow and Flame, since those will give you the seeds for a pretty solid Noldor deck). In general, the Dwarrowdelf player cards are better than those in the Shadows of Mirkwood cycle, but you'll need Shadows if you're interested in an Eagle deck.
Regardless of your play style, the Khazad-dum expansion is a great purchase. It's especially nice if you like Dwarves (though if Gimli's kin are your favorites, you should be sure to pick up Return to Mirkwood and its awesome hero, Dain Ironfoot). You'll also need K-d and its encounter sets if you want to play any of the Dwarrowdelf scenarios.
Here's a list of expansions in order of release:
-Shadows of Mirkwood cycle-
1. The Hunt for Gollum
2. Conflict at the Carrock
3. A Journey to Rhosgobel
4. The Hills of Emyn Muil
5. The Dead Marshes
6. Return to Mirkwood
-Khazad-dum boxed expansion (need this if you want to play any of the Dwarrowdelf quests)-
-Dwarrowdelf Cycle-
1. The Redhorn Gate
2. Road to Rivendell
3. The Watcher in the Water
4. The Long Dark
5. Foundations of Stone
6. Shadow and Flame
Hope that gives you enough to make an informed decision.