Having owned different modded seats on several bikes (plus several padded cushions and a touring Airhawk), I will only say this: if you value comfort over looks, the thicker the better. Actual material in the seat comes at a distant second but the thickness of the seat is imperative for comfort. For this, you'd want something like the super thick Ultimate seat (Big Boy?) which is butt ugly but extremely comfortable.
I've found that gel as part of the material of a seat along with different foam materials helps quite a bit, although gel alone isn't of much help (e.g. those gel pads that go on top of the actual seat, waste of money). Check out Saddlemen as they do this configuration in their touring seats (gel + diff. foams).
I've ridden cruisers with those sleek looking thin seats and they're torture machines for anything over 15 mins of cruising down town. But they're gel seats, they said; yeah, but gel on its own hardens up after a while as you compress it going over bumps, then you might as well ride bareback on the fender.
One more thing: avoid leather for the seat outer. Not only does leather require a lot of maintenance but it'll eventually let water into the seat which will then ruin the foam and thus the seat's comfort.
Hope this all is of use to you!
Tsukayu VTX hard bags & Tour trunk, Saddlemen touring seat with backrest, NC custom windshield, Risers, LED lightbar, Engine guard LED lights, Cobra fatty guard, Rear engine guards, Fender rail guard, Leather tank bib, Passenger floorboards, 12v socket, ISO grips WITH bar weights, Engine chrome, Triple tree cover, Shaft cover, Fenders chrome, Progressive forks & 12.5 inch shocks, All Balls mod, Chrome clock, Adjustable trunk rack