There was a thread a few months ago about this, with quite a lot of suggestions, not all of which I can remember – and taste is, of course, subjective.
My favourite is Bavaria Wit (I don’t like their lager), followed by Bud Prohibition, although 6 of the latter left me feeling a bit queasy this time last year. I was in our local (smallish) Tesco yesterday and noticed that the range is expanding rapidly, which is a good thing, if only they were to stock the Bavaria again.