I don't have House of Wolves but I noticed running around on the moom there are new enemies and then at some point a key countdown timer appeared. I think I'm supposed to find chest somewhere? Would that have anything I can use.
I've finished Circle of the Moon, Symphony of the Night, and Portrait of Ruin, and played Aria of Sorrow, Harmony of Dissonance, and Order of Ecclesia.
Of those I'd say Circle of the Moon was the best. It was (probably not coincidentally) the first one I played. I played Symphony of the Night later on XBLA, and it held up really well, so I can see why it's people's favorite. It must have been mind blowing when it first came out.
Order of Ecclesia is really good, and has an upgrade system that rivals Circle of the Moon, but it's really hard and I never finished it.
Metroid Prime is one my favorite games of all time. I really really love it, and Prime 2 as well. But I doesn't feel like the same genre to me, mainly due to the lack of rpg mechanics. Dark Souls is probably the closest 3D game to the Metroidania style I've played.
Man I sucked at the bosses. I summoned everything I could and still had trouble. Ornstein & Smough I summoned another player and the NPC and it still took me a couple of tries. Not only did I summon the witch for the butterfly and died several times, I died simultaneous to defeating him. I didn't even know that could happen.
Oddly, I beat the Capra Demon the first time. The only other bosses I got in one shot were Nito and Sif. Even Pinwheel got me a couple of times I think.