Fume extraction has been nagging at the back of my mind for a while.
If you can't get fume extraction for the workbench extract from the room and have a small wall mounted fan that gently blows air across the desk away from the person soldering (but not enough air that it cools the iron). I would not even attempt any welding, machining or grinding in the same space (as some have suggested) you are going to do electronics work leave that to the workshop where you can get sweaty and where it doesn't matter about metal shards getting into every nook and cranny.
For your work benches consider benches that you can work comfortably at while you are standing up as you don't want to be crouched down "head over desk" all the time whilst seated. Make the benches so your arms are almost at right angles to the work area whilst standing then buy some quality "bar stool" sized height adjustable chairs. Bench construction should be marine ply (not crappy chipboard or MDF - blech). Mine are 32mm thick and will easily take 100Kg, YMMV.
For the chairs consider dentist style saddle chairs that can be raised to bar stool type heights with a circular footrest. The reason is you may find yourself working on something and getting up and sitting down kinda gets annoying. If you have to sit for longer periods of time at the work bench that's when you use the stool when you get sick of sitting you can stand and still work - much more efficient. You'll also find that you are more energised while you are working especially if you can stand, work and move. Enough has been said about power and storage but you may want to consider that the power has ground loop cut-off for safety if you are working on mains-rated gear so you can minimise the chance of electrocution. A second smaller shelf or other arrangement that suits you to mount oscilloscopes, multimeters, lab power supplies and some mounting underneath to get the computer off the ground (if you really need one there at all) so you don't kick it all the time or bang it with your knee - have up to four ports wired into the wall to under the desk that you can use for ethernet (cat5/6) usb and rs232/432 to suit your needs.
Have some separate lighting for the workbench beyond room light, a quality florescent with diffuser mounted just above the workbench that illuminates the work area generously (not your eyes) and can be switched on and off easily in case you need you use a magnified work lamp as well. Have this above a 100mm vice that includes an anvil space behind the jaws and has a mount that you can rotate. Mount it on a corner of the desk so that you can re-orient it 90 degrees. Buy a quality British, American or Australian made vice, more than likely the British vices are probably the best. You will use the vice more than you know - also have aluminium and wood vice guards that you can interchange handy.
You will get burnt, you will get cut so mount a first aide kit on a wall nearby and also mounting space for safety gear like eyeglasses and hearing protection. Consider using the fine grade mechanics gloves that still give good feel for when you are working.
This is basically the set up I have, obviously you have to consider the workbench for your needs and the stuff I have here is just the basics. When you construct the space consider what you need to do in such a way as to minimise the clutter. I have not even gone into tool selection/mounting because that is going to be dependent on what you are trying to do - but mount your tools so they are accessible and easy to put away - nothing slows you down more than not being able to find what you need quickly.
Hope this helps.