Left 4 Dead Achievements: Valve Lets Us All Know How Lame We Are

I've slowly been pulling myself away from the siren's call that is achievement whoring. Don't turn your nose down at me, you know you've been tempted yourself. Inevitably I wind up getting pulled into just about every title I play to some degree before I can reaffirm the the fact that gamer score mean nothing.
Then Valve had to go and post the the achievement statistics on Left 4 Dead. It is really quite impressive to know that it's been a week since the release of the title and there are still things that people have yet to receive, or at least no one statistically:
- LAMB 2 SLAUGHTER: As an Infected, incap a Survivor who has entered and left a safe room.
- ZOMBIE GENOCIDEST: Kill 53,595 Infected.
Ok, the genocidest one is less surprising, that's a lot of bodies to kill. The full list is kinda fun to dig through. It is for me at least, as I am a statistics junkie.








Hey, the Genocidist achievement does make sense; it's one more then the number of zombies you have to kill in Dead Rising, which was the total population of the town the game was set in. A little nod to the game, I suppose.
I'm kind of surprised that stuff like "Finishing the No Mercy Campaign" is so low down, statistically. Obviously people are favouring the versus!
Looks like my "best" achievement to date (and by best I mean the one the fewest other people have earned) is "Do Not Disturb". What's everyone else's best achievement so far?