A few interesting titles worth watching:

Historical:
- The seven samurai
- Saving private ryan (only the first half is really good though)
- The guns of Navarone
- Gladiator
- The Great Escape

Fantasy:
- LOTR trilogy

Western:
- The good, the bad, the ugly
- For a few dollars more

Gangsters/Mafia:
- Godfather I, II and III
- Once upon a time in America

Prison movies:
- the Shawshank Redemption
- Papilon

Misc. action:
- Goldfinger (Bond)
- Thunderball (Bond)
- Hunt for red october
- Payback

Terrorist movies:
- Arlington road

Drama:
- Citizen Kane
- Fight Club
- American Beauty