I know everybody loves French, but I personally hate it (probably exactly because it’s so overrated). I find Dutch extremely cute, and I also like Portuguese for some reason. I find Finnish extremely funny, as well as Xhsosa (not sure of spelling). Not necessarily “nice”, but intriguing.
Another quite intriguing language is Romanian, which has Latin roots but a lot of Slavic influence (due to geographical reasons). And Lithuanian, which is a language I’d definitely love to learn if I could.
Generally, I speak 7–8 languages (only 3 fluently) but would like to learn as many as possible.