Out of what's been mentioned that I've played.
Paid full whack for Mirrors Edge on release and enjoyed it. Wasn't keen on how it succumbed to putting in shooting but you weren't forced to use weapons, still a shame that they felt they needed to include them
Brothers in Arms, the first one in particular was special and a nice change to the formulaic fps style.
Nexus The Jupiter Incident,

So pretty, great voice acting and atmosphere. Love it!
Deus Ex: Invisible War, sure I enjoyed the first more but it didn't stop me having a good time in Invisible War.
Prey had some really good location design but it just felt like it was wasted and would have been served better by being more open in how you progressed through areas as opposed to the corridor shooter it was.
Beyond Good and Evil was just awesome. Great characters, writing, art style and sense of fun, pity it wasn't more successful.

Couple I've got that I liked and enjoyed even with their flaws despite either being slated or not being a commercial success.
Stolen, Alone in the Dark (most recent), Boiling Point, Risen, Unreal Tournament 3, Velvet Assassin, Urban Assault, XIII.