The tires on it now are the H2 700x35mm.
I was thinking of replacing these for summer commuting, mostly paved paths and road, with something a bit easier rolling thus Marathon Plus was recommended and I was going to go with 28mm tire. Also, I was going to look into 28mm gatorskins.
But if I will gain nothign really other than "maybe" more puncture protection, cant say that I care and it will not be a worthy upgrade for sure.