[Kuruharan]

Rohan's is a 'death &/or glory' culture, very like that if the dwarves.

I beg your pardon?

Eowyn (Eomer) and Fingolfin

I’m going to deal with both of these at once because they are rather similar in my mind (sort of).

Eomer reacted in a passion during a period of intense stress. Such things are a natural part of combat. This in no way indicates that Rohan had a cultural policy of foolhardy battle-mania wildly driven on by unchecked pride. As I noted above, Theoden (who died in a way befitting a hero of that mode) never displayed that type of behavior. If he had he would have bravely charged the army guarding the road rather than chicken-heartedly going through Druadan Forest

In conclusion, Fingolfin was full of ofermod, and his actions had good effects, and did not harm anyone else but him.

Fingolfin just sort of snapped. After the crushing defeat in the Battle of Sudden Flame, he just went a little funny in the head. Note the words “a great madness of rage was upon him.” I don’t believe that chivalry or pride had much to do with what happened. He just went crazy.

Anglo-Saxons

But Anglo-saxon generals weren't 'sensible'. It was about more than simply winning, it was about winning honourably. Beortnoth believed, & so did his people, that a victory gained dishonourably was a moral defeat, & that it was better to go down fighting & win the moral victory.

If I wanted to be flip I would suggest there to be a strong correlation between this and the reason why they ultimately fell (or, in fact, fell several times). However, I have too strong a sense of history. The Anglo-Saxons were not as simple as that and they were not lacking in an appreciation of practical results as compared to moral victories, in spite of what their literature could lead one to think.

While this is probably not the place to discuss this at length, but just to provide a few instances:

King Harold Godwinson at the Battle of Stamford Bridge caught King Harald Hardrada with his pants down (or more accurately, with his chain mail off) and Harold singularly failed to do the honorable thing and allow the Norse to retire to the other side of the bridge, bring up reinforcements, and get their armor on before he pounced upon them.

King Alfred at the Battle of Edington not only sensibly snuck up on the enemy at dawn, but he seized the high ground and attacked the Vikings by charging down the hill to give his men the best advantage. That doesn’t sound terribly sporting to me.

in their ofermod is darkly attractive

Perhaps these types of characters are best used to inspire people when they need to do something that must be done that (hopefully) cannot be avoided or dealt with in a better way. Perhaps it can even be used when the people in question are actually operating from an advantage.

Aragorn and Company

& live to fight another day, or stage a tactical retreat, regroup, & make an organised assault on Sauron later. Aragorn decides to throw away his own life & the lives of his major allies - Eomer & Gandalf.

They could not retreat. They would easily be overtaken and surrounded. Once they were there they had little choice but to continue their little diversion on to the end. They would all have been killed anyway, in very unpleasant ways if they had surrendered.