Depends if you plan on building alot of enclosures. If you have any intent of making and selling them
1. . Compass, protractor, angle finder if you can get one cheap, a calculator, pencil and paper.
2. Plunge Router, flush trim bit, asstd roundover bits, 1/4" & 12" straight cut bits, and a circle jig. Hands down the end all be all for cutting perfect holes.
3. Lots and lots of clamps in assorted lengths and function.
4. Table saw. For the time being a couple clamps, a straight edge, and your circular saw will work .
5. Decent drill, counter sink bits. Some use a brad nailer also.
For starters //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif