The fact that Halo has co-op is far enough for me to say it's better.

But clearly Halo 3 was terrible.... otherwise why isn't there a Halo 4

Halo is better in my opinion.

Metroid Prime is better in my opinion because it has exploration elements as well as being a shooter / 2D platformer.

Not to mention it is more original. Im sorry but if Master Chief was more slender, and red instead of green, I could see somebody gettin sued!

As a standalone game tho, Halo is still one of the best first person shooters of modern time.

there is Reach...which should be its equivalent.   there is also odst coming out in sept.  if they end up making an actual numbered "4", it will likely be a launch title for the next xbox.

I was mocking you MrBubbles for your silly assumption that after a trilogy has ended Nintendo should continue along the same path. And that somehow Nintendo making a non-prime metroid game means they admit MP3 was bad.

I have already witnessed 2-3 people since reponding to you that have claimed MP3 the best of the Prime and or Metroid games in total.

Star Wars - A New Hope, Empire Strikes Back and Return of the Jedi.

Halo.

Metroid
because

1) Samus.
2) it feels like a puzzle/platformer sometimes not all shooting
3) Samus.
4) its more fun, and more unique
5) Samus.

i didnt comment about a continuation of the Prime series.   a sub-series can end and continue with similar style and gameplay.  

regarding your second comment...

"Those who can make you believe absurdities can make you commit atrocities."

"They were so strong in their beliefs that there came a time when it hardly mattered what exactly those beliefs were; they all fused into a single stubbornness."

"The object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane"

that last one may not really be fully applicable since i dont think thats a view of the majority.