omega-3 fish oil

what is more important DHA or EPA? and is there a brand I should check out? HDL and LDL out of range low.

By "top quality" I mean in terms of purity, freshness, strength...I'm already aware of Nelson's recommendation, Nordic Naturals, but are there others? I've been using a bottom shelf brand, but I'm going to switch after reading about rancidity in many brands.