Here is the list of High End Cpus.
http://www.cpubenchmark.net/high_end_cpus.htmlFor your gaming PC, ignore all the Xeon Cpus and simply compare the scores of the I7, I5, I3 Cpus.
For Graphics cards, here is the list of High End GraCards
http://www.videocardbenchmark.net/high_end_gpus.htmlIgnore stuff like Quadro, because these are not made for gaming and are not worth their price if you only play games.
For ram, I suggest getting a minum of 8 GB for gaming, Though personally I would go for 16GB
And another important thing is getting a SSD. It does not have to be huge, just put your Windows System on it, and install all your games on it.
They will run A LOT faster if you install them on the SSD. For old games that is not needed, but new games like Battlefront3 can make very good use of the added speed of the SSD.
Additionally you should obviously also get a TB or more SATA Drive, for storing all the other stuff that does not need to be read/written super fast. You know, music, pictures etc.