Like mrjamwin said.... many (most?) of the BF2 hardcore players have moved on to Battlefield Bad Company 2. That is where I spend all my time these days. That said, Battlefield 2 was the game that sucked me away from my addiction to Star Wars Battlefront II.
I'm sure mrjamwin is right about a dramatic drop in BF2 servers but...... I would venture a guess that there are still enough of them (even US based ones) to get your money's worth out of it if you enjoy the game and you computer isn't up to "snuff" for the demands of Bad Company 2.
Mandalore wrote: Then again, it's still a top 10 game on xfire, if I remember correctly.
Battlefield series=squad based, strategic positioning, twitch based aim
Call of Duty Series=1 on 1 based, tactical positioning, twitch based aim
+1 to this....
If you just wanna run around by yourself in a shooter... COD would be fine. Personally, I really love the teamwork aspects of BF2 and that is what really distinguished it from SWBFII for me, getting me totally hooked on it in the process. I also bought COD4 and played it a little, but never really got into it....was pretty to look at but was missing that teamwork element...
Now... to be honest, many of the things that promote teamwork in BF2 did not make it into Battlefield Bad Company 2 that I'm playing right now. I'm hopeful that Battlefield 3 will bring some of this back. What Bad Company 2 did was bring the destructible environment that the Frostbite game engine can deliver. There is just something really cool about being able to dramatically alter that playing landscape. You are NOT safe hiding behind walls/trees/sandbags etc... since the enemy can destroy your cover with the right firepower...