I'm also going head over heels for the do-it-yourself thing. The most expensive tools you need are going to be (in my order of importance):
1. Fletching Jigs
2. Arrow Saw
3. Bow Press
I use the jigs more than any piece of equipment that I have, and I've owned a bunch of different styles. I use to think the Bitz jigs were the "cats meow" and they really are if you are shooting fletch over 2". If you are shooting Blazers-Fusions-AAE Max Hunters, Predators, etc...you are going to be better off buying one of the newer jigs made just for them. There are 3 that I know of: Bohning Helix & Helix Tower for Blazers, and the Arizona Archery Mini Fletcher. They all 3 put the same degree offset and helical on the 2" vanes. The new for 2010 Tower does 3 fletches at one time and so does the Arizona Mini. Beware though that both the Helix and Helix Tower will put the vanes on very near the rear of the shaft...too far back IMO.
Arrow saws, there ain't much to choose from. And if I knew then what I know now, I would have just built one and saved a lot of money. I got an Apple Pro Saw 8,000 RPM for my birthday this week and I was rather surprised at what it is, or lack of what it is rather. If you have a way to mount a Dremel tool with thin cutting blade, and a place to mount a ruler...you basically have the Apply Pro saw.
Bow Press -- A must for tweaking the strings/cables and replacing strings/cables and or retying center serving, etc. BUT unless you do this a lot or work on a lot of your friend's bows, I personally can't justify getting a $500+ press for that little amount of work. The bad part about making such an investment is that with bows always changing designs and such...that your press may be obsolete in a couple of years. But if you intented on keeping the same bow for several years then it would be okay. The alternative is one of the cheaper "break down" presses for around $100. They aren't as sturdy or mountable like the more expensive counterparts, but I'm a lot more comfortable spending $100 for doing peep tying/center serving, and such...than I am for spending $500+ to do it.
The rest of the little gadgets you can get here and there and soon you'll have everything you need. You'll need to add little things like the nock & d-loop pliars, butane torch, arrow spinner, arrow squarer/deburring tool, nock gauge/t-square, etc. Not to mention a good supply of fletching and glue. I've used Bohning Platinum fletch glue for years and just recently switched to the Goat Tuff glue. I'm using the Goat Tuff for all my fletching and insert installation now and I highly recommend it. I've fletched 5 dozen arrows and installed inserts in all of them so far with a 1/2 oz bottle and I've still got a half bottle left.