Shashka. I love it. The stab isn't horrible, and contrary to what some may think, stab on horseback is a phenominal way to kill shit. It's best for killing other cav, and you end up using it like a really short lance.
Stab isn't necessary, but it REALLY helps when doing the 1h cav shit.
It's also the cheapest sword that's above 100 length (I could be wrong). Upkeep ain't a problem with it, thats for sure.
The disadvantage is its slowness. Not a problem when on horseback, but when fighting on foot it is. You can try to compensate by using your range advantage, though.