Are you taking requests? -- No, and I have no intention of doing so in the future.
Are you taking commissions? -- No, but if you find me at a con and buy me enough Scotch I could be convinced to scrawl something on a napkin.
Can I use your art for an avatar, banner, wallpaper, etc? -- Yes, with credit.
Can I use your art as a base? -- No.
Can I copy your art as part of an educational exercise (mise au carreau, etc)? -- You know you're supposed to do that with good art, right?
Can I use your art in a RP? -- Sure, but don't tell me about it.