Each pack adds stuff to the game.
However, the only way to take advantage of them is play on servers specifically setup for them.
I got the packs too, our SGS servers were always empty so I had to play on INT servers and I got kicked alot because of my ping (I have a shaped account).
To really enjoy those packs, get a unshapped account and play on the INT servers (local just won't work)
But ya, basically, those packs just gather dust because if i play on local, i only play the normal BF2 and OCCASIONALLY the SF pack.
Oh, I wanted to add (after the fact) that I don't play BF2 anymore... ONLY COD4

but having said that, BF2 is still an amazing game, I just got bored and needed something new...
