Ok heres the deal i want to go out and purchase Battlefield and after a quick look on the web im not sure which is the one to buy, i want to be able to play online etc...

Input please

They do have battlefield 2 complete package, which i think might be the correct choice, but i like you am unsure about 2142

Forgotten Hope 2 is coming for BF2. But 1942 is also a good experience (STUKA!).

I only have BF2 by itself. I don't have any expansions or Mods.

Buy BF2 then download the 1.41 Patch.

America's Army is good for a while, but you can get burnt out on it easily. For the BF games, I recommend Battlefield 1942 and Vietnam (both come in a cheap combo pack now) and then download Desert Combat 7.0 and Final (for 1942) and Point of Existence (for Vietnam) Also try Interstate 82 (for 1942). There's plenty more ad-ons for them, and they're smooth on even old PCs. Also, the average players aren't a bunch of nublets like in BF2, and most don't hog vehicles or base spam. Also, the helo flying in Vietnam is (imo) funner.

BF2 (with expansions) and BF1942 are the best ones.

I haven't tried BF2142, but from what I've heard it contains spyware to produce in game adverts by examiming your web history (so you'll probably get a load of adverts for planes, or something a little moe tasteful )

So I'd say get BF2 or 1942, butnot 2142

Why get 1942, it is a dying game, I like the game play in it but i hate getting on and there are no servers. I have BF1942 with Forgotten Hope, and Eve Of Destruction. I loved EoD. I have BF:V with Point of Existance and EoD. BF2 with the Special Forces, PoE2, the American Mod deal, EoD mod, and Desert Conflict. I just got BF2142 with no mods.  All in all I loved BF1942 but BF2 is fun, it's still alive and the Desert Conflic mod dosen't have any kiddies. BF2142 is the BF2 engine, it is fun for some quick action. I say go with BF2.

Now, for those of you looking for realism I have no clue why you are trying that with BF2. Go out and buy Armed Assault. It's engine is made from the engine they use in the simualtors that help train the United States Armed Forces. They don't call it a shooter it is listed under the "Simulation" genre. I need to say they are right, for a few reasons, the people that play the game are big on teamwork, the map would take you an hour to run from one end to the other and all battles take place on this one map in different cities towns with different enemy styles etc. In multiplay since it can often be a long way to battle people are a lot more cautious of dieing. The graphics are very very pleasing.

If im looking for some quick run and gun action I choose Battlefield, if I want run and gun with a hint of realism I choose Desert Conflict mod, if I want "As Real As It Gets." I play ArmA or I head down to 4th Recon Bn and get knee deep.

No idea, I don't look at frame rates in games (save FSX) I ran it fine on 1 GB ram, a 7800GTX, San Diego 3700 at 2.7 Ghz, it ran on Medium/High settings. Now once I got 2 GBs ram it became a whole lot better and I was able to raise my sliders even more. Even on medium settings it looks great. No worse performance than BF2 I will tell you right now. If you would really like a frame rate reading I will go dl FRAPS and measure.