I believe the number sits somewhere around 789 or so regular releases not including Platinum hits or demos, and I'm not sure that includes 2007.
Here's a few that depending on where you live may be hard to find. These are based on talking with collectors, reading forums and ebay prices:
AirForce Delta Storm
Baldur's Gate: Dark Alliance II
House of the Dead III
Jurassic Park: Operation Genesis
Marvel vs. Capcom 2
OutRun 2006: Coast 2 Coast
Samurai Shodown V
Shattered Union
Sniper Elite
Sphinx and the Cursed Mummy
Steel Battalion
ToeJam & Earl III: Mission to Earth
Tom Clancy's Splinter Cell: Chaos Theory [limited Collector's Edition]
Ultra Bust-a-Move
YMMV however, as some people find these dirt cheap, others search in a 500 mile radius and find nothing. But if you see any of these cheap, don't hesitate. I'm sure others will pipe in with a few i've forgotten. There's a guy at DP who has a complete US set, it was around 790 or so.