I use the Rode NT3 quite a bit for this type of thing. It has a good high output and a pretty uncolored sound. I have even used it on vocals (though not my preferred mic for that). I own three of them and find them very versitile.
You can find them new for under $200 if you shop around.
I don't see anything wrong with having two mics from the same manufacturer. Rode has a good reputation for quality products.