I hear good things about Over the Hills and General d'Armée looks really good. Got the rules, but haven't gotten to play them yet.
Then of course (if you don't wanna be bothered with formations and micro-management like that) I strongly suggest Blücher by Sam Mustafa. He's really, really good at abstracting games so that they're fast and fun, while keeping the period flavour. It's corps-level (as in you command a handful of corps) and works wonderfully.
If you elect to skirmish, I don't think that there's any need to look further than Sharp Practice.