Mechanical pencils are a must for me. I have no idea why anyone uses anything else (unless they're doing a fully-shaded pencil drawing). I tend to draw on 11x14ish animation paper stock, since I have about 4000 sheets of it left over from college, and I refuse to get rid of it. Otherwise, I'd use a standard Strathmore sketchpad.
For inking (if you're not doing it digitally), I recommend
Staedtler Pigment Liners. I use the smallest -- the 005 -- for pretty much everything, since I can get the most control out of my lines. Plus, it's killer for hair. For large black areas, I'd use india ink, but since I've never found a brand of ink that doesn't come out splotchy, I usually just do fills in Photoshop.
Another way to go is to use a brush to ink like many professionals, since you get nice variations in line thickness that would take much longer to artificially create with a pen. (They make 'brush pens,' but the only ones I've tried have come out in a semi-transparent purplish-black color, which isn't all that helpful in contrast to the dark pen lines.) I suggest you check out
gouache, which is something like a cross between ink and paint (watercolors prepared with gum); it's incredibly versatile. You can use it like watercolor and make great translucent washes, or you can leave it very opaque and inky. The best part is that, unlike paint and ink, it usually dries with a very nice solid matte finish. Alex Ross works almost exclusively with gouache. I would too, if my brush skills were better.
I've always wanted a figure model, but never got around to buying one. Instead, the best thing I learned in college was to use photo references. If you have a digital camera, set the timer and then pose yourself how you want -- you can always exaggerate and stretch it while you're drawing. Take a few hours and get photos of different people making as many different expressions as they can, from different angles. One of my jobs is to take portrait photos of people with a digital camera, and over the past couple years I've amassed a giant database of some 20,000 different faces to use as references, which I frequently use for my other illustration jobs. A genuine, real-looking facial expression can make a huge difference in a piece.
If you're really serious, I'd also get a drafting table. They can range from relatively cheap to super-expensive, but working at an appropriate angle can really be helpful. I've tried art boards and everything, but they're usually too enormous or too tiny for whatever I'm working on.
As for colors... you might as well do it digitally. Unless you're doing a straight
painting, or refusing to go scan your work, digital colors will almost always look cleaner, crisper, and nicer, plus you can still have plenty of painterly effects with them. If you're going au naturel, I'd either go with gouache or watercolor, or just dump the 'drawing' bit and do an entire piece in pastels. I think that pastels are really underrated, but your mileage may vary. Some hate them, but I dig the hazy thing.
Oh, I have a
Rolling Ruler, too. Mainly for moments when I'm too lazy to actually measure distances out. Use with caution, since the stupid thing is almost incapable of making parallel lines more than 1/3" apart, before one of the wheels slows or catches or something.
And
THIS is probably the single most important art supply you will ever use.
