Think about it for five minutes, take a shot, first thing you see is the tattoo, go to the first tattoo shop in walking distance and then do it. FOOLPROOF[DOUBLEPOST=1363889970][/DOUBLEPOST]Okay. So, more seriously.
Find a design you love, and keep it somewhere at work or at your desk at home that you'll see it for hours a day. Still like looking at it after a week? Two? Start thinking about where you would want it placed, both strategically if you have to cover it up, and personally/aesthetically. I can't really help you on design, since "geeky nature" covers an immense area of ground. I can say, "Get a 20-sided die on your wrist, cover it with a watch at work." but if you don't play dice games, well, that's useless
Meantime, you research tattoo shops. Call them up, talk to people, view their portfolios online and in person. LOOK AT TATOOS/PHOTOS OF TATTOOS THAT ARE HEALED. I cannot emphasise this enough. Fresh tattoos often look vivid and excellent, even when they're not done especially well. Look at healed tattoos. Look at healed tattoos. Look at healed tattoos.
If you have transportation, look outside of city, or even outside of state. You might find stronger tattoo culture and tattoo shops in other cities that aren't too far away.[DOUBLEPOST=1363890045][/DOUBLEPOST]And keep that design hanging in your sight for like... a month. Maybe two. Make sure you ain't tired of looking at it.
Also if you're the type to get seriously regretful and feel embarrassed/ashamed of past choices, tattoos may not be for you.