i5-2500k is hands-down the best value gaming CPU on the market today. You will not go wrong with that.
The fx8120 may win some straight benchmark tests just because it's an eight-core, but look up some tests for gaming performance and you'll see it getting murdered by four-core Intel Sandy Bridge CPUs. AMD completely screwed the pooch with its new generation of CPUs when it comes to gaming; they may have a lot of raw power, but they're inefficient as hell at using it for games.
The CPU ranking charts on this very site don't even have it within three tiers of the best gaming CPUs on the market; the i5-2500k blows it away, and it gets beaten by last-generation Intel CPUs and some two-generations-ago Intel CPUs, as well as certain last-gen AMD processors. Basically, avoid the hell out of Bulldozer processors until they either fix what's wrong with them or programmers figure out how to design their software to be more friendly with them.
That leaves you with the case and hard drive to consider, but those are no biggie. You might consider a little bit better motherboard than the one I listed if you're going to do anything really advanced, but for general gaming purposes you probably won't notice any difference.
Yes, this is probably going to cost you $100-$200 more than the Tiger Direct kit, mostly because they were able to keep the price of that bundle down by skimping on the video card. One case where you do get what you pay for.
tyvm for this reply is very helpful so i have a gigabyte 550 ti OC atm in my current system so i decided i wanted to put my own system together so all i need is everything minus the card and as far as motherboards go ill have to serch more so that i make sure when i build this i get the most bang for my buck using my takes to get all of this all i got to spend is $600 max
one more question whats a good case that gives good flow for a good price under $100 prefer
You can often find it for less than that at a brick-and-mortar store - the Fry's near my house often has them for, like, $44.99 or $49.99. Cases are one thing where it's definitely worth checking out a local store, since the shipping costs can be a lot (and even if they're listed as free or cheap shipping, it's built into the overall price online).
Definitely keep looking at motherboards, but like I said, stay away from the $200 ones bevause you're wasting your money unless you're planning on doing some advanced stuff, like crossfiring multiple cards, or setting up an absolutely huge RAID array, or overclocking so much that improved northbridge cooling makes a difference, etc. The "elite" boards look cool, but for 99% of people out there, a $75-$100 board is the sweet spot; just make sure it has SATA 6GB/s and USB 3.0 and it'll last you a long time.