Out of all the games (Warning, a bit long)...
Leader: Kieran Amell, Warden-Commander of Ferelden, Chancellor of the Realm and Bann of Soldier's Peak, Blood Mage spec.
Nathaniel Howe. My favorite companion! I don't know who wrote him, but he's fantastic in every way - quiet, dignified, intelligent, proud and principled yet not letting those very qualities dictate his every action, has a rockin' bod (although every man in Origins has the exact same body model except for Lloyd - does this mean Lloyd is the sexiest man in Thedas??) and I'll admit when Awakenings first came out my Warden had more than a little crush on him... anyway, in my personal canon Amell cedes Amaranthine to Howe after the Architect and the Mother are dealt with, letting him run it for the good of well, everyone.
(I can't imagine the nobles of Ferelden ever accepting a mage as liege lord, while Amell himself has little desire to rule over a bunch of terrified, unruly mundanes who will never appreciate or understand him. Warden-Arl Howe will keep the more restive elements in line, while preserving a thread of legitimacy to appease the most die-hard Landsmeet conservatives. Soldier's Peak and a parcel of land to support its garrison are enough for Amell, thanks. He also has the Chancellory to attend to - and Howe would be an immeasurable help in teaching him how to administer things and be "a noble." Plus, he can blame the whole "giving Amaranthine to the Wardens" idea on Eamon and the Guerrins while working on stronger ties with Fergus Cousland and the North.)
Jowan. He was intended to be a full companion anyway, only scrapped at the last minute. I can't think of a reason not to conscript Jowan - executing him is a complete waste of resources, same with rendering him over to the Circle to be made Tranquil. Of course, my Amell has the reason of a lifelong friendship to save his life, but even so, Jowan can be immensely useful. And he has good reason to want a mage friend at his side who isn't a notorious flight risk (Anders), a homicidal, racist maniac (Velanna), or a preachy Loyalist abomination (Wynne). Two blood mages can do many things. With Avernus, that makes three, to help shape Ferelden into a nation to be respected, rather than the pitiful backwater canon is insistent on it remaining to be.
Ariane, Dalish warrior queen. No real reason other than I like the cut of her jib, and she's a wickedly powerful warrior. Ah, dual-wield warriors. Thedas shall never be the same after your loss. ...Perhaps she opens up a connection for better relations with the Ferelden Dalish?
Rogue, warrior, and two mages. Adventuring party standard!