I don't have any yet, since I'm only 16, but I plan on becoming a tattoo artist professionally so I definitely want them. And a lot of them. And if possible, I'd like to have all of them either be my own original drawings or from photos that I took.

I haven't decided when it'll happen, but I'm absolutely 100% dead set on having Kat Von D do my tattoo of Ramses.

As for your tattoo, if you tell the artist in the shop that you want to cover up the cross with a snake, they can usually come up with something pretty good on-spot. However, if you want a solid idea before you go in, I can do a quick sketchup for you for free or a real, finished version for a small price. And so you know I'm not drawing squiggly lines and calling them snakes:
http://novaluna.deviantart.com/gallery/#/d2yfn2a
http://novaluna.deviantart.com/gallery/#/d2xypl1
http://novaluna.deviantart.com/gallery/#/d2o6kyo
I should probably stop before I get in trouble for posting an ad or something (Sorry, mods! Wasn't my intention!). So I guess if you're interested, send me a PM, and if not, well then good luck, and I can't wait to see what it looks like finished!