Pretty-much all correct, with one caveat that I'll add - if you're dropping (*relative to the other components) "big coin" on the GPU, and a (*SATA) SSD, then it's really not going to break the budget, if this rig can take DDR3, to boost the RAM to 16GB (either two more 4GB sticks, if it already has 2x4GB, else 1x8GB if you already had 1x8GB, or 2x8GB if you had 4x2GB).
IMHO, these days, if you're going to play newer games, to avoid sudden frame-drops, try to have 16GB of RAM installed. Most AAA games that play better with 16GB of RAM installed, will have that listed under their "recommend" specs. Also, consider that Windows 64-bit likes to take 1.8-2.0GB for itself, somewhat, and that depending on the GPU's VRAM size, Windows likes to mirror the GPU VRAM in normal system RAM as well, for some usages. These reasons are why I suggest 16GB as more-or-less standard/minimum, if you intend to play AAA games. It's generally not a necessity just yet, but it does, IMHO, make some difference. NOT as much difference as spending that money on the next-higher GPU tier, though, generally-speaking.
Also, open-world games, like Fallout 4, Skyrim, and the upcoming CyberPunk 2077, most likely benefit more from greater RAM amounts, since they have more to hold simultaneously in their "world", rather than an on-rails FPS shooter, like Crysis or Metro games.