I run Schwalbe Big Apples in 2.35″ (c.60mm) and love them. (Not cheap though now, foldingd for £35 each, rrp is closer to £50!!!).
I tried some alternatives recently and didn’t like them as much. Big Apple 2.0″ (50mm) is nowhere near the volume of the 2.35″ and measured up more like 45mm. Some of the Conti range go up to 700x54c but the one i bought to try only measured up to about 47mm in reality which was a tad annoying (how do you undermeasure a slick tyre??).
The Big Apple Folding and Conti (Sport Contact?) wire bead will be up for sale soon if anybody is interested (less than 10 miles on both).