Really,
unless you're an achievement whore why would you want to max out a game? I haven't maxed a single one, the closest I've come is the excellent Bad Company 2 where I have most of them but the motivation to replay any game on "super ludicrously hard" was killed stone dead by accidentaly playing CoD:WaW on Hardened.

That teeth-grindingly infuriating experience made me vow never to bother with anything other than Normal again and as to collecting 1 million collectables for a 20 point achievement, no fucking way.
(The man with the flan swashed his buckle on, Sat 26 Jun 2010, 19:17, 2 replies)

I prefer the achievements that make you slave through thousands of collectibles
to the ones (e.g the first two in Assassin's Creed 2) where you get chunks of gamerscore simply for sitting through the opening sequence without pouring beer in the Xbox or hoofing it across the room.

Achievements where you gain a little for a lot of work are disproportionate.

Achievements you cannot avoid getting are retarded.
(Falstaff's Spiritual Successor, Sat 26 Jun 2010, 21:26, closed)

Spawn/grenade/death
COD:WAW on Veteran was horribly unpleasant. Harder than all of COD4, including the Mile High achievement. Bastard thing left me with gnarled claws for hands afterwards.
(square go, Sun 27 Jun 2010, 23:07, closed)