Well, I just mentioned it in another thread, but Crusader Kings, long a buggy and struggling contender, has been significantly redeemed with the latest patch ( 1.05). Battles are largely abstracted, so none of the Total War experience. But as a strategic RPG it’s tops in my book. My book being written by a medieval history geek ;).
Starting from a historical European setup ( 1066, 1187 and, I think 1337 ), it’s a dynasty builder. NOT a state builder, which many new players don’t quite get right away. This was before the age of nationalism. Half the fun is watching fortunes fluctuate from generation to generation - seeing your brilliant strategist, valorous, just and wise king with great stats conquer and inherit a vast empire stretching Gibraltar to the Alps, only to see his first three sons die of disease and on the battlefield, to be replaced by a worthless schizophrenic, excommunicated, wastrel of a loser who loses 3/4 of it to rebellion. Great fun :)!
And the role-playing possibilities ( again, if you’re a huge geek ) are endless. You could start as the count of Vermandois in 1066, his son and heir also heir to the Vexin and Amiens and the last direct male-line descendant of Charlemagne, and try to rebuild Carolingian glory.
Or complete what Roger II started and conquer Tunisia for the d’Hauteville’s of Sicily.
And why should the Langue’Oc rule the day? Start as the duke of Toulouse and replace the Capetians on the throne of France with a proper Occitan-speaking monarch.
Strategic marriage, assassinations, claim-grabbing, excommunications, war with the heathens. What more could you ask for?