Questions about field/engine equipment have been answered.

As for building, you have gotten some good suggestions about basic ARF supplies. If you're going to build a kit (something I think everyone should try) I'd like to add some more to the list.

Keep in mind that I've only built 5 kits, so I'm far from a expert. This is what gets me by.

1. Good, sturdy, FLAT table that is long enough comfortably fit either the length of the fuselage, or half of the wing span. More room is better as it will give you places to work while something you just glued is setting up. Most kits require that you build a left and a right wing, then join the halves sometime later. The table must be FLAT. Also make sure that the table is FLAT as well as FLAT. FLAT is something that is very desirable in a building surface. It is also good if it is FLAT. Did I mention FLAT? If it isn't flat you'll end up with warps in your finished product, and a plane that flies as well as your table would.

2. A measuring tape (flexible) with 1/32", and metric graduations.
3. An assortment of very straight edges. I would suggest 3', 18", and 6".
4. 2 "T" bar sanders. A 3', and a small one, maybe 6", and an assortment of rolls of sticky backed sandpaper to use with them.
5. Several sheets of sand paper of various grits, from 180 grit, to 600 grit.
6. An Exacto knife or 2, with lots of spare blades. Dull blades will ruin a good cut every time.
7. Hobby saw. Get a fine tooth and a coarse tooth blade for it. A Miter box is also a pretty good idea. Exacto makes them to fit the hobby saws.
8. A razor plane.
9. Glue. Thin CA, Thick CA, Wood glue, 30min epoxy, and 5min epoxy.
10. "T" pins.
11. Some scrap balsa of various widths, thicknesses and lengths. You can usually buy a bag of scrap balsa with a good variety of sizes at your LHS (Local hobby store).
12. Clamps. Small ones, medium ones, big ones. Not big ones that steel workers would use, or even furniture builders, look at the selection at the LHS and pick out a variety. Get plenty. A good substitute are those black paper binding clips that you see at most offices. Use them wisely, they're usually strong enough to damage or break balsa, but they work great on plywood or hardwood.
13. Tape
14. A covering iron and socks. You can use a regular clothes iron if you don't care about looks, or peeling Monocote, or people laughing at you. Get a heat gun too. The $15 one at the LHS will do. If you already have one that you use for peeling paint you can use that, but only if you don't mind burning holes in your covering, and rebuilding the sections of your plane that you either set on fire or ruined when you had to put out the previously mentioned fire.
15. A good hobby sized square. Also a smaller 90* square that will fit between ribs.
16. All of the previously mentioned hand and power tools.
17. A pin vice.
18. Epoxy mixing cups.
19. Rubber gloves. It is rarely mentioned here, but epoxy on the skin is not only hard to get off, but the chemicals in epoxy will seep right through your skin. They aren't filtered out of you blood stream by your body, and over time they will build up and cause nervous system problems that are not reversible. I'm sure it takes years of regular exposure to cause problems, but an ounce of prevention is worth a pound of cure.

20. I'm sure that most people here have lots of other tools that they use, and they love sharing their knowledge, so by far the most valuable tool for building these wonderful toys is . . . RCU!!!!!

Good luck,
Jet