Hardest Xbox 360 Achievement

[Sleep]

ok guys post what you think the hardest achievement ever is , i would say Mile high club on cod4 was hardest but i have done it several times so im going to say the hardest achievement IMO is

GRAW 2 - World Champion - Climb to the top of the online Leaderboards

so yeah guys post away

[Sky-]

I still think Mile High Club. Took me a good few weeks to get it.

[Extasey]

The co-op vidmaster achievement on Halo 3.
Lag made this achievement IMPOSSIBLE. fudge you Australian ISP's.

[Sleep]

hmmm mile high club was hard but i dont think anyone now will ever get the world champion achievement and the vidmasters were reasonably easy with 4 halo veterans

[Extasey]

Yeah, the achievement was easy to do, but because I could never set up a game without incredible lag... it became impossible. Once we managed to get to the down ramp for the last jump, then the host lagged out :|. The whole team lost their enthusiasm after trying for an hour and a half...

[Sleep]

dude the same crap happened to me 1st time round my mate had dinner so he quit as we were jumping game ended ARGHHHH hulk smash i went bezerk :L

[Poppins]

There is one on Call Of Duty MW2 I was told (not sure if it's true.) Where you have to wipe out the entire team with a care package. Seems pretty hard.
-Poppins

[Genequil]

I'd say Mile High Club was one of the hardest I've done. There are some other achievements that require a shitload of time (like Seriously 2.0 in GoW2), but aren't actually hard. I've done Mile High Club twice on my profile, and once for my brother, so I don't know.

[Sleep]

hmm yeah i have done mile high club several times myself and have done both Seriously 1 and 2.0 legit ( time consuming ) and poppins thats not an achivement its an ingame challenge i think for multiplayer you get a title or emblem for it

[Silver]

I still think Mile High Club. Took me a good few weeks to get it.

That achievement took all day to get, I swear.

It's not the hardest, but the most time consuming one was Seriously on Gears of War.