Twinings makes a fairly acceptable earl grey.
Coffee Bean & Tea Leaf's earl grey isn't too bad either.
Stay away from Fortnum & Mason.. it tastes like donkey jizz. Not that I'd know what it tastes like. Honest.
I like many different teas.. Earl Grey coming in the lead, especially good with some cream and sugar.
Asian teas are good too - Jasmine, Hoji-cha, Genmai-cha, oolong, and on a hot summer's day, iced mugi-cha (barley tea).