Wipe-on-poly is a good choice if you're looking for maximum durability. However, like other polyurethanes, it gives the surface a plastic look without a lot of depth. It also won't "pop" the grain; for instance, it won't get the deep, wavy look out of curly maple. Polyurethane also ambers over time.
If you're using an expensive veneer, shellac or lacquer (the latter only if you have adequate ventilation) are better choices because of the clarity and depth they lend to the wood. Classic fine antiques were done in shellac; nowadays fine furniture is done in lacquer for speed reasons, though shellac is still much more common among hobbyists because it's nonvolatile and nontoxic. Shellac only provides average durability, but it has the advantage that dings can be touched up years later, because a new application melts into the old.
Under either poly or shellac/lacquer, you can enhance the grain with a light application or two of boiled linseed oil diluted with turpentine. This helps most woods, but on some, e.g. fir, it may make them too dark for your tastes, so experiment first.
An alternative to the suggestions above is an oil-based finish like Danish oil or Tung oil. These are easier to use than most any other finish, but they penetrate into the wood and aren't designed to provide a uniform satin or glossy look without multiple applications. Most modern formulations contain some varnish for durability.
