I agree withthe Talley system. Mr. Talley is a great person to deal with btw, he is VERY concerned about quality and reputation. Even at full retail the steel 2piece setup is only $100-$125 or so. Is that really THAT much for THE most crucial link between you and the game animal? And besides that, they will last you a lifetime. You may change scopes and have the gun worked on but you will NEVER have to worry about the Talley steel system.
I have used the alloy 2 pieces for over 2 years now and they are GREAT. I wouldn't worry about them on larger calibers. I have them on several of my guns. I doubt any big game caliber would shell them, they are T7000 grade aircraft aluminum with VERY heavy, coarse threads holding the rings together. I have sold HUNDREDS of pairs of them too my customers and not one single failure has occured.
My third pick is the Opti-Locks on my Sako. I replaced them in 04 after a trip from WYO. The Burris rear windage screws could be turned by hand!

I bit the bullet and immediately put the OLs on. I wish they were available for other makes of rifles!
I also have a couple of guns with Leupold dual dovetails. They are MANY times better than the standard turn in front/screw down rear. But they don't have as much surface area as any of the above rings.
Just my picks,
RA
ps
Oh yeah, I have Warnes on two of my rifles. One a quick detach setup on a muzzleloader and a permanent rig on my 700 Custom Shop. They are basically copies of the Talleys and I have NEVER had the first minutes problem with either. You just don't see them in many gunshops.