Ok, Im going to try this again.. stupid wireless....
Ok, so sorry for chiming in late, been preoccupied... lol

Here is what I have used for the costumes Ive done.
1. My first and most favoritestssss cheap tool... The snap off razor knife from the dollar store. U can usally get 3 for a buck, and when they are dull.... you snap off a new piece. I would say get about 6 or so. It should be more then enough to get you through your armor. I pick up a handfull everytime Im in there.
2. Dremel... Dremel.. Dremel...(and a snake) holy cow, I did my first set by hand, mostly, and wow... what a difference. Like Mow said, a diamond blade from Lowes is worth every penny of $15. For the set up, you will spend about $100. But man... the time and effort alone.. sheesh.. totally worth it. BUT... you dont have to have it to finish your armor. OH.. and a palm sander of sort.. dont matter which one.. it makes the difference...
3. A good sharp pair of scissors.They will come in very handy.
4. GOOD painters tape. The cheap kind will let paint bleed and does not stick for poo. I found out the hard way.
5. Jo-Anns snap tool. Not the hammer and plate, but the plyers style. Do like they say and watch for the %40 coupon.
6. Good cutting board of sorts.
7. Personal prefference.. CA glue from your local hobby store. I used it on 3 sets of clones and a Vader. Worked very well. I also used it on clone shoes instead of shoe goo or E6000.
8. Magents, magnets, magnets... Holy cow, I learned a new love for them. Both in putting the costume together and in useing them in the costume itself. Also, many clamps too. They still come in handy.
9. A metal straight edge and pencil.. I know.. its dumb.. but needed.
10. Like Jaster said, pencil soldering iron, unless you dont have it, just a normal one works, but I seen his and that thing was cool... I mean his soldering iron.. pervs...lol
11. MAYBE.. a heat gun. I didnt use one, but some people have had to pending on body shape.
12. I use "All purpose" bondo from lowes. It seams to stick better to .. well anything. It also bends abit better, but its still bondo. fyi.
11. Like Terrell said, 100 to 800 grit sand paper. U still need to do some hand sanding...
12. And Im sure I missed something... but lots of BANDAIDS!!!! trust me... you need them.. lol
I dont use snips to cut anything on my armor. I dont like the edge it gives. But.. these are my personal choices. They work for me. You might find this is the worst list in the world... I hope not.. lol, but.. Im sure you will add to it and take away from it as well!!.
If you have any other ??'s , just give me a yell!!