I just found the cooking vessel that will truly change a lot of my culinary life. It's from Williams-Sonoma, but I found it in an antiques mall in Cayucos, CA when we were up the Central Coast on vacation. It's a double boiler, though it could also be used as a bain-marie, with a deep copper lower pot, and a heavy white porcelain upper one. This has a round bottom on the inside, flattened enough on the outside to sit on a flat surface. The copper handle is fastened to a copper band, with a screw adjustment to remove the handle if necessary. This had been priced at $165, marked down to $135; we've found that it's still listed at W-S for $230.
My first thought was that this is what I'd want if I decided to try making hollandaise, and in fact it might convince me to try doing that. It's also going to prompt me to get more into custards - I don't like sweet ones at all, but the potential of savory ones is something I'd like to explore. When I made mac'n'cheese the other night I made the bechamel cheese sauce in this, and while it took a bit more time the velvety-smooth result was a revelation. My next experiment is going to be using it for my overnight-on-the-hot-tray steelcut oatmeal.
Knowing what I know now, I think I'd be perfectly willing to pay retail for this thing, if that was the only way to get it. Besides, it's so handsome I don't at all mind the fact that I've got no cupboard room for it; it looks really nice sitting on the cooktop.