Depends on your taste, and how you drink it. I drink my tea plain, no milk, sugar, honey, lemon... and I don't like most brands like Lipton, Twinings, Dilmah or Pickwick because they're too bitter and have little tea-taste.
We go to a local tea shop to buy loose tea. I prefer the smoother black teas like Java Kertasari, Yunnan Flowery Orange Pekoe, Kenya Flowery Orange Pekoe or Ruhuna Orange Pekoe. Phreak prefers the (very) strong taste of a black assam called Sewpur Broken Orange Pekoe.
If I really want to indulge myself I go for a cup of Kusmi tea. Nice smooth and with some added flavour, like violets or citrus fruits.
http://en.kusmitea.com/our-teas.html