For nail guns and occasional texture work, I recommend a 24-liter compressor with at least 200 liters per minute (e.g., Abac Bambi 24/250 or Einhell TC-AC 240/8/10). If you plan to do texture work more frequently, a 50-liter model (e.g., Scheppach HC100D) would be the better choice.
DIY
For DIY - this is also a placeholder.
I don't have much to add, since I haven't made the switch to pneumatic tools myself, but one bit of advice is to make sure you're using hoses with as wide of an internal diameter as possible. The connector at the ends is often wider than the internal hose diameter, which is what really matters for long hoses. If your chosen compressor is really loud, then you might want a longer hose to put it farther away, but then have to contend with the hose being a flow-rate constriction.
I never considered that, thanks for the input!
I use a small, 3 gallon pancake type compressor for nailing and inflating 99% of the time. For rare use, rent a bigger compressor or it will just take up room and not really be portable.
I was thinking about renting a big one for spraying, but I'm a slow DIYer. It would end up costing me a good chunk of change to rent compared to spending a bit more for a bigger one up front.
Thanks everyone! I think I'm gonna spring for something a bit bigger, maybe 8 gallons and 4-5 scfm.