I swear, you're an idiot. You consider MGS3 a spin off title (though it has all the gameplay mechanics of the MGS series), you have no proof the MGS series has sold more than Halo series yet you laugh at vgchartz's charts (the site you're posting on) and bring up Wikipedia out of nowhere, and some other nonsense.

Stop pulling out random numbers. Thank you.

True, prequels usually don't sell quite as well. But it's still relevent that no MGS game has outsold a Halo game.

GTA Vice City is a prequel to GTA 3 and has sold more than it.

But really, this idiot thinks MGS3 is a spin-off title.

Maybe 'spin-off' isn't the best description, but it shouldn't be compared to Halo 3 which is a direct sequel. And no, it doesn't feature the same character, Big Boss is a different character to Solid Snake. If there was a choice, then I wouldn't compare it to the sales of Halo Wars, but it's the most appropriate.

The original Metal Gear Solid outsold Halo. MGS2 is debatable depending on whether you count Substance or not.

I see your point but things are a little different. No one gives a rat's ass about story in GTA games; it's all about running over prostitutes and taking their money.

On the other hand, the only reason I suffered through the terrible control system in MGS2 & 3 is for the story. 

Halo 3 has already sold 6 million in only 2 months and the Halo series is pretty well known for have very long legs. Halo 2 just sold 9k copies last week for example. Halo 3 is well on its way to beating even Halo 2's sales.

Big Boss and Snake look exactly the same and has the same voice. Hell, people thought it was Solid Snake before the end of the game.

Stop using Wikipedia numbers just because they back up your opinion. Seriously. You're only making yourself look like an ass.