Did would depend on what type of accuracy you wanted, the average Lasers typicaly are out by a few degrees over several meters unless you buy a laser set-up designed for acurate set-ups $$$$. They act like transit's (or theodilites).
Precision leveles are the normal way for machine builders to level with accuracy, providing the machine itself has a precision surface to mount the level., but these too can be quite expensive ($500-1000 for 8" level)
A regular torpedo level and a real keen eye can get you most the way if you are not after thousands of an inch for accuracy.
Once you have it set-up, consider benchmarking key items or better yet drill and dowel pin for location, you can buy metal dowel pins that are threaded, to remove easier with a slide hammer, simply returning the dowel pins to their holes at set-up will gaurentee accuracy as metal dowel pins themselves are usually accurate to within a few thou of an inch. Drill rod can also be used as dowel pins as it too is very accurate........