There are a lot of great suggestions from the folks already but I'll throw my .02 in. My shop handles woodworking, machining and car/moto repair. 20 x 36 x 9.
Tools... Focus on the big three and fill in the rest.
Table Saw - used 3hp cabinet saw with a BIESEMEYER fence or some copy of it (Powermatic, Delta, Jet) If funds are available, buy a SawStop.
Jointer - 6" will work but I would prioritize an 8". More capacity and like others have said more mass. I have the Powermatic 60. Buy one used. Once set-up, it is a great machine. Helical cutter is nice but for a hobby, I would wait and see if it becomes something you can't live without.
Planer - I would recommend a 15". Yes they take up more space than a portable but it will serve you a long time. This can be purchased used.
With these three you have a good solid machine base that can take stock and get it square and straight. I would lay the shop out so these can be in a fixed position. Add in a chopsaw (or old radial-arm), router table and assembly bench and you are in business.
Dust collection - Cyclones are great. Combine that with an ambient air cleaner and you are well on your way. If funds or space are tight, the single stage will also do the job, just not as well. (OMMV)
Here is the layout...
Material Storage is a big thing. You will need somewhere to store sheet goods, hardwood and cutoffs. Here is how I addressed it. Both the cut-off cart and the sheet goods cabinet are on wheels.
Cut-off cart and hardwood...
The hardwood storage is 2x4 's on end with 3/4 emt. Nothing fancy.
Sheetgoods...
I know that I got a ton of inspiration from other threads and photos. I suggest that you look through the shops here on GJ and PM a few folks. It's a great group here.
More details, don't want to hijack, on the solutions I used are in my build thread. My shop build out is still in process.
Hope this helps. Good luck!
Cheers,
Chris