It is not essential to stain timber prior to finishing. Often stains are used to disguise the fact that low quality timber is used. I prefer to show off the natural beauty of the timber without any staining and generally use a polyurethane satin finish after applying a sanding sealer to fill grain. Below is a maple desk finished this way.
Daves right, the natural look is great. I also use polyurethane
to get a beautiful finish. One thing to add is that if you would like to enhance the grain try staining with a water based black aniline dye. Once stained resand the surface until just a faint amount of the stain remains. You will be amazed how the figure pops out once you put on the polyurethane.
I make quite a few things out of both hard and soft maple, and have always used Natural color Watco Danish Oil. There's really no need for a hard poly finish on hard maple in my opinion. Before applying the finish I buff the wood with a fine foam sanding block, like the ones made by 3-M. This creates a slight gloss and seems to bring out any three dimensional grain effects too.
Just yesterday, we used clamps after glue simply to take the bow out of the wood we were using, and it straightened everything out for us. Usually though, any time you lay up a project the clamps are...