This is actually a really good question. FPS is my favorite type of online game for console by far. Call of Duty and Battle field both have its perks.
I guess the question lies within you. What type of FPS are you looking for? One that is more arcade style, or one that is more realistic.
COD is arcade. BF is realistic. In COD you will most likely be running around like a mad man blasting everything that moves.
The maps are small which allow for constant action and the game gives you plenty of replay value as it will take many months to rank up completely. In BF you will be sneaking around searching for cover and hiding from enemies a bit more. You will be looking for advantage points.
It is a much slower pace than COD due to the huge maps and has a better use of terrain and environment. If I were to choose, it would be BF. Reason being is that it feels much more life like than COD.
The perk with COD though is the awesome customization the game allows, which is limited in BF. When I play COD it feels like a spray and pray type of shooter, whereas BF feels like every bullet counts. There seems to be more pride in killing someone in BF than COD in my opinion.
BF is more along the lines of "I found ya, now I'm gonna wait for the perfect moment to kill ya". COD is more along the lines of "There you are in plain view now point and shoot". Both games are extremely fun, but I find more enjoyment playing BF.
I guess it's just more fun with bigger levels, many vehicles (COD has none), and environment destruction. Oh yeah, one other thing...BF has global stat tracking while COD only does a measly individual stat tracking. For a newbie in FPS games, you can't go wrong with either or.
COD is more promising in terms of pick up a controller and play than BF. But if you're looking for a more realistic simulation than BF is the way to go.
PLaying on a console and just want to run around shooting people then get into the COD series. Pc gamer and want a bit more of a challenge and team work then get into the BF series. You can pick up BFBC2 pretty cheap and try that out before they release BF3.
BFBC2 is a really good game but its got a steep learning curve you will get owned for the first few hours you play :P.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.