The older label making tape is very good stuff and its still available in well stacked stationery shops,
I've had good luck with Bare-Metal's scriber, Tamiya also makes one, but I find it a bit big and awkward in tight places. As for needles in your chuck, it all depends on the kind of needle you use, theres as many different needles as there are sewing techniques out there. I've had the best success by using glover's needles in my number 1 Exacto knife handle, I have to cut their shafts down a bit so there isn't too much play in them. They have a three edged point thats usually hardened to some degree and I find they cut a much sharper line than most other needle types.
If you're trying to restore detail on the flat surfaces of your model, say a fuel cap on the wing somewhere, one of the best tools I'm aware of is a draftsman's erasing shield. Its a thin flexible piece of metal, usually about the size of a business card with a good variety of shapes cut out of it. You should have no problem finding one of these at any drafting or art supply store. Staedler makes a very good one and I've never seen this item to be terribly expensive.
Hope that helps