Which Air Compressor should I buy?

Agreed, get something small for portable and put some money toward the big boy. My 5hp 60gallon is a single stage and it will do anything I need. I haven't tried to sand blast with it yet but i expect it to handle that. I can run cut off wheels and impact guns for a good while before it even kicks on and it takes 20 seconds to pump up and stop even with me running tools