I got a taste for traditional Rum Punch in Barbados last Easter. There's a great little rhyme that sums up the ingredients...
One of Sour
Two of Sweet
Three of Strong
And Four of Weak
...which translates as
1 measure of lime juice
2 measures of sugar syrup
3 measures of rum and
4 measures of water!
It has to have a little grated nutmeg over the top when you serve - delish!