In my opinion, you cant go wrong with a 300 win mag or wssm. You can custom load this caliber like crazy to shoot flat, fast, and accurately. I have two loads for mine that shoot very similar. One is a 165 grain and one is a 200 grain. I know its not a "different" caliber, but there are a lot of different loads you can run in the 30 caliber. I shoot my 30-06 more than anything, but you can get something to shoot much flatter than a 30-06. I would definitely look at the versatility of the rifle if it is that hard to find a rifle (I'm right handed so I don't have that problem). I like a 30 caliber for shooting at big game, but I have killed some deer with my .243 as well.
As for the scope, all I shoot is a regular Leupold 3x9 duplex, so I can't speak for the more tactical style scopes.