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.
High-velocity fans are also an important tool in their own right, particularly at your finishing station. Increased air flow will help dissipate fumes from paints and sprays for your safety, and you can train a fan on your project to help paint dry more quickly between coats on humid days. To get the most out of your fan, look for floor fans that are easy to aim or wall-mounted fans that will save space in smaller shops.
My shop consists of a 9×16 storage building, with 3 feet being used for actual storage! I have a table saw, 13″ planer, lathe, sliding mitre saw, home made router table, small compressor, 5′ 4 drawer bench with vice, table top drill press, 6″ jointer, band saw, shop vac, wall mounted hand tool storage, clamp rack, power tool storage, and no room to turn around! But I put out a few nice pieces! Recently built, a 48″ entry table from 100 yr old milled poplar, coffee table from the same re milled red oak barnwood, and a little triangle shaped corner table from the left over red oak, a 7′ x48″ bookcase from old poplar, a small wall mounted poplar book case, and am presently working on a queen sized bed with a mixture of 100 yr old oak and new kiln dried oak, with drawbored pegging using black walnut from a tree from my yard! I’ve also made several mallets that I find useful from my firewood pile using Cherry, ash, hickory and white and red oak. Building anything in 108 sq ft is a challenge, but patience determination, and decent sales will make it work! One good point is that nothing is out of reach! Except maybe the bathroom!