How acceptable is it to omit "da" in casual speech in phrases such as
-- chokoreto ga suki (da) yo
-- boku wa daigakusei (da)
And so on..... Do it also depend if it's a male or female talking?
I think omitting "da" in casual speech is common.
I feel chokoreto ga suki yo is mainly used by female. If you omit だ in だよ like that, it becomes ladylike manner of speaking.
boku wa daigakusei is no problem. Or rather, that kind of だ is commonly omitted in casual speech.