Im going to throw in my suggestions for:
Fishful er, Fistful of Lead, FFoL Bigger Battles and FFoL Horse and Musket.
I personally really enjoy these rule sets, they're very easy to pick up, very easy to tweak and modify and can be easly tailored to any setting. I use them for BoB shenanigans as well as War of the Roses nonsense. They're toolbox rules, so you have to design and stat out your units as you need them, but I find them very well balanced, interesting as a d10 system and I just love the playing card based random initiative system. And for a few dollars you can get each rule book in PDF form from the Wiley Games websitem.