+1

Agree with RO2 (and Darkest Hour).

Brothers in arms series is good for single player, you direct squads as well as fighting yourself. I'm replaying hells highway at the moment about operation market garden.

I had BIA and the authentic maps are great but the gameplay is intentionally porked by forcing you to do flanking manuevors on almost every target. THe devs force this to suit the gameplay ideas. You could be 20 feet from a kraut standing behind sandbags and wouldnt be able to shoot him becasue of some invisible barrier, you would have to flank him to get a kill shot.

Wait!
 

HOOOOOOOOOOOOOOOOLD ON!!!

What about the medal of honor series!!!
MOHAA :O (The d day invasion was awesome - same time period as saving private ryan/ The band of brothers? - as a young teen, i loved it!)
MOHAAS :P (Jumping off the C47, British Enfield... mmm :))
MOHAAB :)
....
ill admit tho, MOHPA ... my pc couldnt run it at the time :'(, not to mention the game engine was s**t?
MOHA brought it back! (Loving jumping into the 'soup')
MOH Tier edition 1 is ok, but i have completed the single player campaign

I also enjoyed playing DOD's (Day of Defeat source) but this is all multiplayer based!
I own RO1 & 2 - never got to the online gaming with no 1 much, but i tend to enjoy that RO2 battles - shame they couldnt get it right on release...

Hidden and Dangerous 2 was another good game!

I would also mention:
Return to castle wolfenstein
BIA Road to hill 30
WW2 GI

fun times