Well you mentioned Angmar and you are looking for a heavy infantry type to support your rangers, so why not keep the theme and use Arnor. The Miniatures you will have are limited (Arvedui: king, Malbeth: magic, Command blister and Warrior blisters). But you will have the option of adding Minas Tirith to your allies so more defence 6 soldiers at your disposal plus a number of heroes and siege engines etc. Grey Company isn't that fun for either player but you can use those rangers as the Arnorian rangers.
Angmar has shades, spectres, wargs and trolls as well as Warg Cheiftain, Burhdur and Gulavhar so plenty to pick from. You don't need orcs although they are filthy cheap so I personally would take some. The wargs make decent alternatives so long as they have terrain cover. A pack of trolls is a scary thought. You can also take the Witch King although Gulavhar is my preferred choice.
Keep clear of the elves (unless you mean the armoured ones). The wood elf sculpts are awful so painting them becomes a pain and they are quite limited to one troop choice with defences 4-5. I suppose if you like quicker battles wood elves are the way to go
