I bought a three-pan non-stick aluminium set from Aldi a couple of years ago for about seven quid. I've been very pleased with the pans, although they have no bail and the pot gripper that came with them is no use.
I have a few other sets but for two people backpacking I think that's what I'd take. The Trangia sets aren't cheap, they aren't all that light, they're fairly bulky and they rattle unless you stuff things in them to stop that. You definitely want something with a capacity approaching two litres for two hungry backpackers. One litre is never enough for me on my own, I usually use a two-person set just for me.
I think more important than the pans is what fuel you use. For backpacking I'd want as much as possible to use wood (and likely rubbish left around by other people) foraged along the journey. That way I wouldn't have to carry so much weight in fuel. I'd take a small supply of polythene bags to keep the soot on the bottoms of the pans, and not on everything else. You don't really need a stove for burnng wood, you can stand a pot over a fire with something as simple as three tent pegs pushed into the ground, or if the pot has a bail make a pot hange from a couple of tree branches.