I've been knee deep in this genre lately. Picked up "The Twin Snakes" for GC and played it for a bit. Restarted my "Syphon Filter 2" game from awhile back and have (finally) made it more than half way through. And I've been pondering the purchase of "Pandora Tomorrow," "Omega Strain," and "Everything or Nothing" (I'll get 'em all eventually, but only one at a time .
So I want to know - what's your favourite series of this genre? And if which game specifically (if any). Which series do you hate (if any)? If you could make the ultimate Stealth Action game, what aspects would you take from each game?