As far as the basic supply list goes, I like to keep things easy. The philosophy behind my tool selection is simple: how well does it work versus how much does it cost? Bearing that in mind, of course I end up doing a lot of my work with Sharpies: they are cheap, available, have excellent color saturation, and are increasingly on the market with new colors and specialty tips. Some of my favorites are the 80's Glam Color pack (in fine point) and the brush-point markers. Here's a couple of photos of random Sharpies in my bag at the moment:
I also like the extra-fine point Sharpies for detail work, but lately I have been mixing things up a bit after discovering these excellent pens by Stabilo. Much like the Sharpies, they are cheap, come in a staggering array of colors bearing excellent saturation, and also last a good long while. Here's a few examples of the 20 or so that are currently stuffed into my little bag:
Last but not least...is my circle tool. I do a ton of complex geometric pieces, as you might have noticed, and for the most part end up freehanding the vast majority of my shapes. But sometimes you need a clean circle and that can be...difficult. Just ask Giotto! This little piece of scrap metal gives me 2 circle sizes, depending on whether I circle the interior or exterior rim. I picked it up for a nickle in a scrap metal bin at the Scrap Xchange in Durham, NC several years ago. It has served me well.