Neither!
Depending on who you talk to these to terms can be either positive or negative. The one thing they have in common is strong passion for knowledge whether it be an intellectual pursuit or one of a more casual nature. Among my group of friends we call each other nerds even though we have geeky passions like video games. In my social circle it serves as both an insult and a term of envy. An insult because you know your friend has been spending countless hours doing the same task whether its playing video games, spending all night studying, or binge watching some T.V. series. A term of envy because I wish I could be doing those things myself (yes I like studying).
The term for me has a different personal meaning but I would much rather be referred to as a nerd than a geek.
what about you?
Neither!
I'm not a teacher. I speak American English. I've tutored writing at the University of Southern Maine and have done a good deal of copy editing and writing, occasionally for publication.
I wouldn't mind being called either of them if it was done in a positive way. I don't really want to be called either of them if it's meant in a derogatory way.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.