Nash's Carbonated Mineral Water (hotels/restaurants only). The cobalt-blue glass bottle makes this Limerick water look terrific.
San Pellegrino Carbonated Natural Mineral Water (Little Italy, 75cl glass bottle 75 pence; some other retail outlets and many Italian restaurants). The fat green glass bottle and traditional blue label make this a classic.
Vittel Natural Mineral Water (widely available, 50cl plastic bottle rsp 45 pence). This small bottle is the size to go for. Young and hip, it looks its best protruding from cabin baggage, sports hold-alls, schoolbags . . .