I like
Atticus. It's not a favorite of mine, but it's a nice, solid name. I feel it's very masculine. I'd probably rate it 7 out of 10. I think it would suit both a boy and an adult. I don't find the -kiss sound at the end off-putting at all.
I'm not sure about a nickname. Attie is too feminine. Ha. Er...I'm at a loss for nicknames...