1. Metal Gear Solid 4: Guns of the Patriots
Possibly the greatest shooter game of all time, it continues and concludes the story of Solid Snake, the super-tough soldier and covert operative. It features exciting, real-time shooting action combined with a focus on stealthy maneuvering. Snake manages to defeat his great enemies Liquid Ocelot and Big Boss at long last, and end the world economy dependent on continuous warfare. The graphics are possibly the best in any video game to date, and the plotline is the perfect cap to the epic journey of the Metal Gear Solid series. Many game review sites have given it perfect scores, and it is considered the greatest game in the franchise.
2. Fallout 3
The best of Bethesda's dystopian future action RPGs, Fallout 3 takes place in a post-nuclear Washington DC / Chesapeake Bay area. The main character, who is entirely customizable, leaves the safety of the Vault in which he / she lives to find his / her missing father and escape from the Vault's insane leader. It features all sorts of customizable statistics, like skills and attributes, that allow you to create a character that fits your preferences. It features the VATS system that utilizes "bullet time" to let you target the weakest parts of your opponent's body. It also has one of the most creepily cute mascots in gaming, the little smiling man on the Pip-Boy 3000. There is so much to do in this game that you will almost never be able to completely finish it.
3. Killzone 2
The latest in the tactical, third-person shooter, PlayStation game series Killzone, it continues directly from the last two games, with the Interplanetary Strategic Alliance sending operators right into the enemy Helghast home planet to take down its leader, Scholar Visari, to end the war. It has superb graphics for the system and exciting gameplay that will leave you sweating. Admittedly, the plot is not the best that a shooter game has ever had, especially considering such series as Metal Gear Solid and Resident Evil. But the gameplay and the online multiplayer is so much fun that you can overlook the storyline shortcomings.
4. Resident Evil 5
The latest game in the Resident Evil series, it features a lot of the new conventions to the series that Resident Evil 4 started, like the over-the-shoulder perspective and the greater emphasis on larger-scale fighting with more kinds of weapons. It also features the return of the original male protagonist of the series, Chris Redfield and the continuity of his feud with the series' central antagonist, the Machiavellian Albert Wesker. It has some of the best graphics on the PlayStation 3 and extremely fast-paced gameplay that will constantly keep you on your feet.
5. Street Fighter IV
The latest installation of the seminal fighting game series, Street Fighter, and the newest numbered game in the series since 1999. It continues the series' tradition of fighting on a 2D plane while utilizing 3D graphics. It also features new special attacks in combination with all the old gameplay that people know and love from the last games. It features nineteen returning characters and about half a dozen new ones. Although it does not have very many additional game modes, the gameplay itself is so solid, and there are so many combo options that it is easily another quality entry in this storied series.