Metal Gear Solid 4 (Truly a great experience)
Little Big Planet (Despite the kiddish looks, real genuine fun that your wife will probably play with you and enjoy as well).
Kill Zone 2 (Just an awesome game, as you apparently already can see).
Uncharted Drakes Fortune (Indiana Jones, Beautiful graphics, Treasure hunting, fun game don't pass this one up). Also the sequel for this is coming for this Christmas. (Might be wise to get this one so your comfortable with the sequel).
Flower (Only 10$ and about 3-6 hours long if you want to get trophies) but easily one of the best PSN games and I guarantee you the most unique, original game that you will ever have played.
IMHO those 5 above are absolutely 'must buys' if you own a PS3.
Other notable games that are a lot of fun but IMHO not necessarily 'must buys' but depending on your tastes would be :
- Resistance 1 and Resistance 2. (Two really solid fun games).
- Ratchet and Clank (Good sold series)
- Motorstorm (Fun off road, mud racing, over the top game)
- Warhawk (Multi-player only game, but definitely a lot of fun tanks, planes, anti aircraft, foot solider, etc You can do it all in one gigantic online game).
- Wipeout HD (Another downloadable game that's a good fun game, especially if you enjoy Wipeout games)
- Gran Turismo Prologue (Racing sim, great series).
