You already have three rifles in basically the same category of rifles. Why add another one. None of the three rifles that you already have will do anything that the others can' t do and neither will the 7mm-08.

Personally I would look for a .223, 22-250 for a varmint rifle or go the other way and look for smething along the lines of a .338 or a big bore lever action like a .444 Marlin, 45-70 or 450 MArlin. Spread them out a little.