I've played pretty much all the MoH and CoD games. The originals from both series were best in my opinion after which the quality started to drop, though I still enjoyed them. CoD has a slight edge for me because the quality didn't drop as much as MoH did.

0.02 cents

I'll take gameplay over graphics, but both is obviously best.

I'm actually playing Ultima 7 at the moment. Compared to anything made in the last 10 years it's ugly as hell but still a lot of fun. Brings back fond memories of many late nights 15 yrs ago.