Real men (and women) drink Yorkshire Gold. If looking for the loose leaf variety, I'm sure that the guys at Singletrack will concur that the tea shop in the indoor market in Todmorden has a wide choice of excellent varieties. The Russian caravan will have you beating off bandits and facing down recalcitrant Yaks in no time.
Supermarket own-brands? Not likely (though I'll drink the M&S stuff at a pinch if I've already been through the compost heap to extract the old Yorkshire bags..)
That said that there Ringtons Gold linked to above looks like it could be a mighty fine cup of char. From what they say on the site, the only way the production process could be improved would be if each teabag was individually rolled on the inner thighs of a lusty virgin. Will definitely be placing my order and taking my chance