Halo is perhaps the worst game I've ever played. Mostly it's because of the crappy Xbox controller that has too many superfluous buttons and you have to use three different directional buttons to do fundamental tasks like moving forward.
I love Metroid. I'm not talking Metroid Prime and all the new Metroids, I mean the classic 2D side-scrollers. Metroid 2 for the Gameboy was the first video game I ever played, way back in 1991. I eventually got around to playing Super Metroid on the SNES, which is still one of my favorite games of all time. I haven't played any of the Prime series because they don't seem like real Metroid games to me. Metroid has traditionally been a 2D game and I think it ruined the series when they decided to make a first person shooter. They need to make a new side-scrolling Metroid for the DS like they did with Metroid Fusion and Zero-Mission on the GBA, that would be awesome.
As for Halo being a rip-off of Metroid, that's the stupidest thing I've ever heard. If Halo is ripping off anything, it's ripping off Doom and all the other early first-person shooters. That's like saying Pokemon is ripping off Final Fantasy since they're both in the RPG genre.