For me, it's always been Sunbeams when I wanted a round wound for rock. They were the perfect string to alternate back and forth from TI's, because their tension and midrange warmth are somewhat in the same league, IMO. For me, DR Sunbeams are the perfect balance between vintage and modern because they can achieve a super crisp top end with zero sacrifice to the all important mids. Tons of bottom end too. I originally went the them because of their tension, round core and tighter outer wrap wire, but I stayed for the tone.
Edit: For the record, I use a GK 700RBII and GK Neo115-III and the DR Sunbeams are the shizzle on my P with that rig. I no longer use TI's (for no other reason than the fact that my attack has gotten heavier somehow in the last year) but IMO the two finest strings made for ANY style are TI's and Sunbeams. If you're happy with the TI's, no harm in putting them back on after trying something else.