I've been a fan of the Bridgestone BT45 tires on my R65 for years, and have been through 2-3 sets. I may never change unless forced, but another tire that I might consider trying is the ContiGo All Around tires - they have decent metric sizes for the front and back, but also do advertize a 4.00" rear. Back in the early 80s, a number of guys and I ran the old Continentals - they had soft rubber and stuck to the road OK but wore out very fast for us. The BT45 tires I use generally get me about 6K miles - I wish it was more, but they stick to tarmac very well in all conditions. Not perfect on gravel roads, but not terrible either.
I've heard of MITAS tires before and seen them on several bikes when I was in Europe, but I have no personal experience with them.