I would like to add a few things.....
1) you get what you pay for, cheap wrenches are just that. Cheap
2) you will end up owning snap-on at some point, so go out and get them while they are affordable now, they don't come down in price, EVER. 1/4 drive sockets are a must-have, so are the off-set open ends. 12 point socket is a lot more useful on a 6 point nut than a 6 point socket is on a 12 point nut.
3) never stop buying tools....buy what you need....if you borrow it once, buy it next pay-day. I don't mind loaning an apprentice my tools once, but not all summer.
4) get a couple of small bush-boxes....1 gets too heavy, and you can't carry 1 heavy box as easily as 2 lighter ones.
5) if you buy a roll-cab, buy a much bigger one than you think you'll ever need, believe me, you WILL fill it. 20 yrs in the Biz, and I seem to out-grow my roll cab regularly.
6) like a previous poster said, buy just what you need for wrenches, but don't ignore the "strange" looking ones, they can be a life-saver. ie: half-moon wrenches ect.
7) build stuff. lots of helicopters need modified or custom wrenches. look in the "old guy's" kit...see what he has made, then copy it.
8) don't cry when you have to spend $$ on tools....without them, you are just a over educated pilot. Take pride in your stuff, it makes it easier to remember to not leave them under the cowls when you paid a king's ransome on a tool. you might have to skip a few nights of beer drinking with the crew until you get your tools, but then you have something to show for it later.
9) remember, you are a skilled craftsman. craftsmen have good tools. home handymen and Red Green have crap tools. You get my meaning? Good...now go make friends with your local Snap-on dealer( or Mac ).