IF you work wood, you NEED a workbench. Surfing around the 'net you will find hundreds of plans for workbenches. They can be simple or high tech, cheap or expensive. The real purpose of the workbench is to help YOU work wood. BEFORE you build one, figure out what kind of woodwork you will be doing. If you need a european style bench, build it. If you want a show piece, build it. If you are like most of us, you just need a bench.
I have a bench in my shop that is UGLY. It was built years ago from pine 2 x 4's, bolted together to form a frame and legs, as well as a shelf support. The top is 3/4 inch ply, screwed to the framework of 2 x 4's. The top has been replaced a few times over the years. The lower portion was covered in ply and doors were added to keep dust out of the cabinet portion. This was done as an after thought on my part but now, I try to put doors on most things because of the ever present sawdust.
The main point is the workbench, regardless of style, has to work for YOU. It needs to be strong and well built, not rickity. It needs to be capable of taking abuse because as you use it, you WILL abuse it. So, build what will work best for YOU and you will be happy. I say this from experience since I built a whiz bang european style bench a few years back that I hated. The tool tray just collected dust. The top was too narrow for me and it took up too much of my precious real estate in the shop. For my style of woodwork, simple works best.