Wow you must really have a hard on for me.
For one my friend builds his own comps. I don't know the spec's, i stopped caring about gaming on my comp 5 years ago when i moved out. Now its just for browsing, Itunes and school work.
As for more than 16 players, this really tells me what type of player you are. Your the guy who wants to be rambo and open up on as many players as possiable. Personally i like smaller games in hardcore mode (hardcore team deathmatch, hardcore search and destroy) or even playing tactical. I am sure you know what these are but big games are for little boys who freak out and throw their controller across the room...
for example:
http://www.youtube.com/watch?v=IrL8J80Ysi8
As for cheaters on PS3 or any console. I haven't noticed any. You can look at the stats and they are ussually banned before they hit level 6 on the first prestige.
to end my little rant, its cheaper to buy a PS3 rather than buying a tower specifically for gaming. I like it better, I stated my point and thats where it ends. Just remember, you can have the best equipment in the world but it won't make you a better player.