ORIGINAL: Hydro Junkie
I've seen lots of good suggestions for tools such as drill press, scroll and band saws as well as the ever valuable Dremel. Two more things that have become must haves for me are a decent sized band saw and a drum/horizontal belt sander. A band saw will do things a scroll saw won't as far as larger pieces go if you're getting into the bigger aircraft. I've found this to be my go to sander, even over my ever present belt/disc like previously pictured, just due to it's versatility:
http://www.homedepot.com/p/t/1000616...71&R=100061671
If you want to see an amazing site for stuff go to "McMaster Carr"