Here's a fellowship of thematic Rohan decks I've been working on for a while - based around the idea of Theoden's last ride to the Pelennor Fields. I've been keeping myself rather strictly to theme by only choosing unique characters who were present at the battle, and non-unique allies who are martial in nature.
http://ringsdb.com/fellowship/view/2994/a-red-dawn
There are a few thematic concessions - Steward of Gondor is the largest one, but I figure that it's rather appropriate given that the Steward - Denethor - called for the aid of Rohan, and so thematically it represents the Lord of the Mark pulling out all the stops to ride to the aid of his ally. Something like that. It's not so hugely out of place as it could be. Gandalf is another one - he was present at the battle but not with the Rohirrim for the ride. Given the ephemeral nature of core set Gandalf, I'm fine with it.
The other thematic concessions are minor - Westfold Horse-breeder is not a military-oriented character, but she was so essential to the function of the decks that she's in there anyways; I think she can represent an army . The Spirit version of Merry might seem counter-intuitive; the Tactics version is tailor made to represent the hobbit at Pelennor, and would also gain the willpower boost from Theoden. But the threat reduction granted by Merry is a good match for the way the Rohirrim kept to secret paths and arrived wholly unexpected at the battle. And my willpower is already bordering on excessive, I don't need extra readying, and above all I needed a Spirit sphere match.
The Tactics/Spirit deck is loads of fun to play. Boosting up Theoden to incredible power levels is amazing - quest for 5, ready and defend for 7, ready and attack for 4. Westfold Outriders give extra attack. For boss enemies, Eowyn + Herugrim does an excellent job. A 1-shot attack for 19 will take down almost any enemy in the game. Witch-kings of Angmar excepted. That one needs Merry, too .
The Leadership/Spirit deck is also fun. I love bouncing enemies back to the staging area with Fastred for Eomer to take out the next round. And hemorrhaging allies only to bring them back is even more fun. Don't be shy about discarding them, or about chump blocking. They'll be back. The best bit is that, unlike the other deck, this deck doesn't require a lot of setup. Just an Armored Destrier for Theoden across the table, and Guthwine and Steward of Gondor for Eomer.
If you use your side quests, take forever, and get all of the potential setup done, then your heroes alone can combine for 27 willpower, and all of them can ready to be ready for combat.
So there's my fellowship. Comments, suggestions, or other thoughts are much appreciated.