Firehawk, thanks so much, that's what I will definitely use. Thanks for all of your help. I'll be investing in an orbital sander tomorrow. I know I mentioned orbital sander in the original post, but it's just a rectangular black and decker that vibrates, not an orbital...
I used birch plywood to make the carcass (sides and shelves). Once I realized that the chinese plywood from big box isn't quite 3/4", it was too late. If you're going to dado, make sure you buy the right size bit or buy 3/4 ply. The bit would have been cheaper if I could have found the odd size.. anyways, it worked out okay.
The back of the shelf is the heavier bead board ply, not the thin slick stock.
The face frame is a combination of 1x2 pine, preprimed trim (basswood? it's really light, and I had it laying around) and some thin 1" pine for the fronts of the shelves.
For the arches, it's the preprimed stick of trim that I had, same dimensions as a 1x4 pine. Had I done this over, I would have cut the arches out of 1x6 material so as to avoid the top trim above the arches.
This is an arch calculator that was really helpful for determining the radius of the circle to use for laying out the arches. I determined the width of the arch and how far into the board I wanted it to go (the height), and the calculator spits out the radius. I then nailed a long piece of scrap plywood to a board, and drove a nail through the other end at my radius length. Center the board and marked the arch. Cut it out with a jigsaw. It showed, but I was pretty steady and a little sanding cleaned them up just fine.
The shelves are just a hair wider then I intended (I tend not to plan the projects in enough detail before I start them. I think I ended up with a 35.5" shelf span, which might sag if I put too many books on them. I also faced the shelves with the quarter inch by 1" pine, which won't do too much to keep the sag from happening.
I still have some 1x pine that I've stained to match the base of the shelves that will overlap the top edge by a half inch or so. I haven't installed these yet because I'm painting the shelves and didn't want to have to cut in around the top board.
Hmmm.... also, ran speaker wire before I put in the shelves and it is routed down the wall, under the wood floors, and up the far wall. Can't wait to get the surround sound going again.
Probably a little more information than anyone wanted to know, but I had a lot of fun building them and learned a lot....
1) Assembling cabinets on a less than perfectly flat surface (two sawhorses and a sheet of plywood) is less than ideal.
2) 3/4" router bit is about 1/16th wider than chinese-made plywood from big box.
3) Self-centering dowel jig needs some adjustment (will be looking into the pocket screws on the next project, firehawk!)
4) Measure for electrical outlets before laying out the shelf height.