I would stick to low magnification, like everyone else here is saying. We have Leupold compact 2X7's on our 45-70's and they have worked great. The Nikon Pro Staff 4X seems to be a good scope for the money. Mainly, it just depends on how much money you want to part with. My thinking has always been to buy the best scope you can afford. This has caused some ribbing from my buddies because the scopes on my handi's cost about as much, or more in some cases, than the rifle.
My next shorter range scope will be the Nikon Monarch African (I think that's the name) in a 1X4. It really looks like a great scope...just gotta save up the cash.
I've never been a big fan of red dots or holo sights. I can see how athey would be great in some applications, I just don't like the idea of a battery running my sight. It would be just my luck to see a 200 class buck and the battery go dead. Actually that wouldn't even matter. If I saw a 200 class buck, I'd be so nervous I'd miss with any sight!