The Great Raid comes into mind as a less well-known war flick.

saving private ryan, where eagles dare, Kelly's heroes, Das Boot, ice cold in alex, the dam busters etc. there are a lot of great ones.

Full Metal Jacket, Taegukgi and Bullet in the Head. Can't be arsed with descriptions, that's what IMDb is for.

Some recent titles I've picked up and enjoyed thoroughly are The Great Escape and Patton.

I second the Band of Brothers suggestion.

I just watched "The Hook" with Kirk Douglas.  A very good study on man's situation during war.  Set during the Korean War, three officers are ordered to kill their prisoner of war.  Very interesting.

Kevin Costner's The War.

Cos it's about one family's war with other familys and on another level, one man's struggle to come to terms with THE War. And it's called The War.

Is this the sort of thing you were after?

Oh. And Predator. It's about this group of elite soldiers and they're havinh this mini war with an alien. Well actually it's more of a skirmish in the woods really. They do some really good forest clearence with some pimped out gun as well.

And Platoon is okay.