"Next gun" for what? Are you using the .30-30 today on deer effectively? You're not having to take shots beyond 150 yards, only hunting deer-sized game? If so - I'd stick with what's already working for you.

If you want to have a couple rifles to choose from, I'd trade your .30-30 for a good .243 and MAYBE (if you ever hunt anything larger than deer) consider getting yourself a .30-06. Between the .243 and .30-06, there isn't a varmint or big game animal on this continent you wouldn't be perfectly equipped to handle.