Shorts - I like Sugois Ultrafino. They're expensive and I'm not real keen on the contrast stitching they now have. But I like the fit and the pad.
Aerobars - Thom put Sedas on the tandem and quite likes them. He says they do take a bit of practice to use. He rode with them on his single for a while before moving them to the tandem.
Chamos Butt'r - sub 50 mile rides I don't usually bother. More than that, I put it on the edge of the chamois. For long days back to back I use it. Always use it on the tandem though, because it's not as comfortable a setup.
V.