I bought some time ago the Medal of Honor Collection pack for the PC, which includes three Medal of Honor games: Allied Assault, Pacific Assault and Airborne.
The first and third games in the pack (third and eleventh in the overall Medal of Honor game series) were quite bleh. They were not bad per se, but somehow I just didn't find them very exciting or special.
Allied Assault has survived the pass of time surprisingly poorly, from a technical point of view. The graphics look surprisingly dated for a game made in 2002. As a game it was quite ok, but somehow repetitive, and at points extremely frustrating (especially in the level where you have to take out all the snipers). The game has a known glitch with some ATI graphics cards which makes it crash at some point, in a later level, so I couldn't play it through. (The problem is aknowledged but has never been fixed for some reason.)
Airborne has much better graphics, being made in 2007 and all, but as a game it was even more bleh than Allied Assault. I didn't find it enticing or special in any way.
However, I really liked Medal of Honor: Pacific Assault. This is the seventh game in the series, and feels a bit like it got drowned among all the other games in the series and didn't get too much attention, but I really think this one is worth checking out.
In later years many games have tried to perfect the concept of immersiveness. In other words, make the player feel like immersed in the game, rather than just watching it from a meter away as an outsider. I think Pacific Assault is one of the pioneers of this genre which, while maybe not the best example of immersive gameplay in existence (that honor probably goes to Mirror's Edge at the time of writing this), still succeeds in it quite well.
The gameplay is very linear, but somehow that bothered me with this game a lot less than usually. Somehow it succeeds in making the linearity not break willing suspension of desbelief so much.
The graphics might be a bit outdated by today's standards, but I still think this is a good game to check out.