With careful planning you can certainly create a useful workspace out of a single garage, but it really depends on your planned activities. If you're looking at machinery, and regular benches think of it a bit like a pool table - that is, you need room for the pool table and a cue's length all round it. Each machine has its own space requirements for footprint, in-feed and out-feed. Cunning use of mobile bases can allow you to reconfigure your layout as you go. Another consideration can be that if your garage is integral to your house you may not be happy generating as much noise & dust as you might in a detached garage.
I share my integral single garage with washer & dryer, bicycle, lawnmower, garden tools, pressure washer, chainsaw, mystery paint collection, cat's litter tray, and more junk than I'd like to admit outside of a support group. I've got a bandsaw on a mobile base, vacuum extractor and cyclone separator, wall mounted air filter, wall mounted timber racks, 4' x 2' workbench with vice, wheeled tool cabinet with plywood top, a Bosch folding workbench and Triton Superjaws - when weather permits I'll sometimes move these last two outside for some tasks. Most of my work is with hand tools, I've got the bandsaw by the garage door for the occasional larger piece, my bandsaw is at the same height as my main bench to allow me to use it as an in-feed support.
I really need to plan things ahead to make things work, I could do with another garage... For me a lot of the inconvenience of an attached garage is balanced by the fact that I can pop out for 20 minutes and tinker at any time in any weather, and things are maybe more secure than they would be in a standalone workshop/shed at the end of the garden.