A good portable air conditioner will also remove excess water from the air, which is critical for keeping your stockpile of wood in good shape. Lumber should be stored in dry conditions so it doesn’t warp, so look for efficiency features that allow you to run the unit overnight in the summer as needed —without worrying about blowing up your electricity bills. Other good features to consider include a thermostat and variable settings that allow you to set your workshop temperature to the perfect level for your comfort.
If you work with rough lumber, a planer will be absolutely necessary, except for the most rustic of projects. Every piece of rough cut lumber ends up somewhat not straight, not flat and not consistent in thickness, either from variations during the sawing or from stresses which occur while the wood dries. The planer, combined with the jointer, is a one-two punch to remove these variations and produce straight, flat and consistently thick lumber. The reason the planer is ahead of the jointer on this list is that some lumber is straight enough and flat enough to plane without jointing if the job is a little less finicky, thereby skipping the jointer.
Other important power tools—A good jigsaw will help get you through many tasks, particularly cutting curves, that would otherwise require a bandsaw. Look for one with blade guides that keep blade deflection to a minimum. A handheld drill is also essential. A quality corded drill is much less expensive than a cordless one, and will never leave you without a charge. Also look for a quality random-orbit sander with a provision for dust collection.
An interesting variation of this layout is displayed in Jim Tolpin’s shop, shown in the photo at right. Tolpin located his jointer to the left of his table saw, its height low enough to allow panels cut on the saw to pass over the jointer. To save space, his portable planer lives beneath the saw. All three tools are oriented toward the garage-style door, which can be opened to allow long boards to be ripped, jointed, or thickness planed.
I looked around at many versions of Taiwanese drill presses. I ended up purchasing the Ridgid DP15501 15" drill press because I liked the way the quill stop was made, the work light, key stor­age, and the easy access to the belt change system. This machine was also on sale when I needed it, so that made it a slam dunk. Choose the one that suits you, as they’re all very similar. The table is large enough, and the distance to the column is large enough to allow you to do most anything a small shop needs. 
If your shop is long and narrow, option 2 provides maximum space to the left of the fence for handling large sheets of plywood. If you often work with full sheets of plywood or other sheet goods, you might want to build the table saw into an extension table surround, as San Diego woodworker Pat Curci did in his small shop (see the photo). The surround offers support for large panels, as well as provides an ample work surface near the saw.