I like
Guy, if said just like the English word. If it's pronounced the French way, I'm meh about it.
Guy feels very beatnik/hipster to me. I definitely see it's potential to be ironic. But it works just fine as a regular name, too - the actor
Guy Pearce has a perfectly ordinary name to me. I know a lot of people find
Guy to be too blunt or weirdly obvious, but I don't think it's any different from any other one-syllable male name.
I always feel like
Guido is a slur? Something about it feels really rude, so I wouldn't feel right using it as a name.