Oregon,
If you want a 2 rifle set, I would go 243, 257 Bob, or 260 for the light rifle, and 30-06 or 280 for the larger rifle. For up to 400 yards, a magnum is not needed IMHO. One rifle in 270, 7-08 or 308 would also do well for a lot of years.
It depends on whether or not you will be...