Stay 7mm & pick your preferred flavor. Just make sure to choose the twist rate that supports what you want to semd down the tube. If you reload, then that opens up all the options. I'm a big 7mm fan.
7mm-08 or 6.5 CM would be my choice. I started my wife out with a 243 that I knew would eventually be passed to my son, then gave her my 6.5 CM so I could justify building myself another semi custom. Terrible I know but it worked out great...sometimes you have to do what you gotta do lol