The freedom to do it all.

[SantoUno]

Oblivion is an easy first in this, followed closely by Prototype simply for the fast and powerful mobility.

 

[Dr Evil42]

I loved Saints Row 2. My friend and I would just do random crap with no pressure to actually do anything. It was awesome.

 

[The Unskilled78]

Garys Mod by far.
Second is either Oblivion or Saints Row2
Third is Fallout3 and Red Faction: Guerilla
Fourth is GTA4.

 

[lapan]

i'm not that much into free-roaming, i always tend to get lost or losing interest. There are a few exeptions like Prototype, Assasins Creed and even Brütal Legend though.