So you're now drinking plain black tea - no sugar or milk?
I can't recommend a brand per se. But I do find that when you drink it black, especially in the UK, you don't need to steep it as long. For some reason I find the tea brews up much stronger here. I also always need a touch of sugar or sweetener if I don't use milk. Lemon is also really nice in black tea (and, as you probably know, the more common way to have it in the US).
I'm a pretty big fan of Earl Gray but it's not to everyone's taste. English Breakfast Tea is also nice.
If you've got time and inclination, going to Whittards or Ringtons and actually trying all their different teas might be worthwhile.