I hate sunscreen, so I'm in the cover-up camp. Long sleeve top, full-finger gloves. Sweat evaporation out of sleeves can really do wonders - have even been cold at moments as I start up after a refill stop.
That said grabbed a short sleeve the other day for an evening ride in the three hours preceding sunset, that was nice, too.
And I've chosen to go with a big helmet brim during the sunny hours, though I sometimes tie it to my back earlier or later. If I were doing roadie speeds that might not work well, but for the long duration of my slower rides it's been key.