If you're buying new I'd go electric as well. I have a 2 gal and it does okay with nailers and quick bursts of bigger tools but that's about it, and it's really loud. The only things I bother to drag it out for are seating the bead on SUV tires and my headless pin nailer for trim. But I bought one of
these for airing up after offroading and it flows enough to seat a bead so now all the compressor is only used for the pin nailer. I don't think there are many electric ones for whatever reason so if you're planning a lot of that air might still be a better deal.
If you are set on air iirc it's cfm @ psi you need to worry about. Look up the requirements for the tools you want to use and work backwards from there.