Hi jermin,
I have little to add to el0375's excellent response above. You are welcome to visit us at ATAG over at
http://theairtacticalassaultgroup.com/forum/forum.php to further your research. The ATAG Server is full switch, full realism and mission driven with clear objectives for both Red (Allies) and Blue (Axis) bombers and fighters alike. That said, anyone is free to fly the experience he wants ie. if you just want to fly a quick sortie looking for a dogfight - great. If you want to hook up with some other pilots to fly the specific missions -- great. If you have a squadron and want to enter as a group -- great.
ATAG also runs a Teamspeak server that any and all are welcome to use. The is no password for the server, there is no charge. Basically the only "rule" we have is that everyone show respect for the other with obviously no swearing or abuse over the chat window. This is a full war server - there are no rules re vulching, shoulder shooting, wheels down no-shooting, etc etc. If you find you're being repeatedly ground strafed, respawn at an inland airfield.
Not sure how well your system will run with a 40-plane scenario (not common in the ATAG server, but possible). Best results are gained with Win 7 64-bit and 6+ Gigs of RAM. Although CoD is a 32-bit system, things will get backed up a bit with CoD using up to 3 Gigs of RAM with the myriad of background processes that Windows 7 runs. Players that run XP do run CoD, but frequently suffer performance problems.
Your GTX 295 card is a good one, unfortunately CoD is not optimized for SLI (yet). I was able to run CoD quite well on a 285 card at medium-low settings; my 560 Ti card made a huge difference in performance. CoD does have a memory leak resulting in a crash to desktop with annoying frequency. A workaround is to delete the cache folder prior to each session - with varying results for each person who does this.
Don't know the cheapest location to buy CoD -- prices seem to vary tremendously.
Good luck and hope to welcome you to the ATAG server.