Walk through my house and everywhere you look you'll see projects I've made from plywood and its cousin, particleboard.
There are two plywood beds, plywood bookshelves, particleboard and plywood cabinets, a plywood table. I write at a plywod desk. I like to use these materials because they're relatively cheap and come in 4' x 8' sheets that make the work go fast and a variety of thickness that suit them to almost any project.
But both suffer from one problem: How do you finish off the exposed edges once the project's assembled? The edges of particleboard have a rough pitted look that is only aggravated by planing. Plywood edges are even worse. The edges of the laminated piles stick out like a score thumb - with stripes - and there are usually a few gaps in the core plies that create holes.
If you're going to paint your finished project - a good idea, since neither plywood nor particleboard looks good in a natural finish - the simplest solution is to putty the edges. My favorite material for this job is polyester auto body filler. You can buy a can at any auto-parts store. It's a two-part plastic putty that trowels on nicely with a flexible putty knife. It sets up in about 15 minutes, doesn't shrink and sands to a good, smooth finish that takes paint like a charm.
For bookshelves I glue on a strip of pine about 1/8" thick. Since most of my shelves are made of 3/4" plywood, I make my own strips by ripping slices off the edge of a piece of 1" pine. The pine is actually on 3/4" thick, so the strips fit perfectly. Once they're glued in place I sand the corners slightly, which gives tham a softer feel and makes them less vulnerable to chipping.
If I'm using a grade of plywood face with a hardwood veneer - usually birch - I like to use a natural finish. So to get edges that match the faces of this plywood I buy flexible wood strips made for just that purpose. They're about 1/32" thick, and you can put them on with ordinary glue or with contact cement. They're usually a full inch wide, so after gluing them in place you trim them with a sharp knife or a plane to match the thickness of the plywood. Sand lightly and you're ready to finish.
Edges of counters and simple tables are easy to cover with aluminum edging strips. These come with special ringed nails that hold them firmly in place despite the fact that plywood edges don't ordinarily hold nails very well.
Another commercially available edging material is the plastic Tee molding. To install this you'll need a power saw. Cut a slot in the edge to be treated, then hammer the molding's flange into the slot. These moldings come in brown and tan, and are made in two widths. One is 3/4" wide, the other 13/16" wide (the right width to cover a piece of 3/4" plywood or particleboard covered with Formica). These strips are sold by Minnesota Woodworkers, Industrial Blvd., Rogers, Minn. 55374.
Ordinary wood moldings often make nice edge treatments, too. For example, screen door molding is just the width you need to cover the edges of 5/3" plywood. And it comes in a beaded section that decorates those edges while it covers them up.