Tough call. I'm a fan of both 7mm and 30 cals! There are plenty of bullet choices available for both, but I guess the 30 cal wins. 7mm bullets are considered slightly superior [for aerodynamics in heavier bullets]. I'd probably just pick up the 7mm-08, as you're already set up 7mm style.

I haven't shot the ultra mags...the 08s, though--both are nice, low recoil, accurate and handy little rifles.