I'm having a hard time believing you're for real BlackTea, but I'm willing to roll with it. I just think it's too good to be true :) i really hope that it is, because it will prove that lightning really can strike twice.

As for clothes... ok, you were (and may re-become?) an otaku. You have some idea what he likes - long skirts, stockings, long-sleeve blouses, cute little shoes, girls with long BLACK hair, sweaters, etc. It's winter, so a little demure and conservative and WARM makes sense. Just pick what you want that's close to something on this list and he'll be salivating over you. I guarantee it.
Remember, he probably likes you (otherwise, why would he be nervous? If he didn't, he wouldn't really care!) He sounds like a nice, smart, sensitive otaku guy who really likes you for you! Don't worry, I'm sure that he'd love to babble at you about whichever giant robot show he's watching right now. And as a added bonus, he probably thinks your smoking hot. You're set.

PS: (Don't worry to much about getting romantic. Just hve fun. If it get's romantic... then it does. That's fine.)