i got BF2 and 2142, so thats Veteran rank 2 in BC2
 
in BF3, my veteran rank is gonna be 3 since it will include BC2, and... bonuses for vets ? cant really think of anything

I actually fairly certain I got most of them (including expansions) except Modern Combat and the first Bad Company...but I can't find my damn cases.

I have 1942, BF2, and 2142. I don't think I've ever used this veteran thing before though.

Right now my rank is1, should be 2, but I can't add 2142, as it just refreshes the page and nothing happens :( I have 2142, BC2 and played heroes for a while. For BF3 probably some weapon unlock that others get at certain level  you'd get at level 1 or something. Or maybe different weapon skin? If so, preferable toggleable.

That veteran system is crap

I've only played 1943 and Bad Company 2. I technically have Modern Combat on the 360, but I have to play an online match to activate it and that is not happening.

Should be higher on the site (I think it actually shows up too high in game) since it still won't take my 1942 (and expansions) CD key, but since it for some reason gave me BC1 Gold Edition for PS3 (and the PS3 demo) I guess that makes up for it.
 
But anywho:
1942 (and Road to Rome and Secrets of WWII)
BF2 (and Special Forces, Armored Fury, and Euro Force)
and BC2
 
If they use the veteran system, they'll probably give vets a weapon or two, but nothing game breaking or unfair.

Got em all, but the 1942 and expansions aren't showing up. Still shows veteran level 8 in-game though.
 
The Bad Company and Modern Combat ones should be attained like any other one. Last time I checked, there were still a few servers running for both games.

Three right now, but it should be five.