welcome! I know this is is a "gaming" build, but you mite get more help posting this in the "New builds" section of TomsHardware. NEway, what kind of games are you interested in? since you have a tighter budget, you mite want to look into AMD. Intel makes very good cpus, but their a lil more on the expensive side. either way you go (AMD/INTEL) you will most likely end up with a nice gaming machine. Have you been looking into any DIY builds on newegg? anything there that caught ur eye??
That combo has three problems:
1. The PSU is crappy.
2. Too much money put into the case for a limited budget.
3. No graphics card (needed for gaming).
You do not indicate the resolution of your monitor, just listing the choices available. What is your monitor's native resolution?
If I remember correctly, FSX benefits from a strong, multi-core CPU more than many games. It may be the case that a true quad-core AMD will perform as well in this game as the dual-core hyperthreaded Intel i3, although it may not in others. Still, I surveyed all of the CPU/game benchmarks at Anandtech this morning, and found that even the weakest Athlon II X2 could play most games well enough. I'm at work right now, and haven't been able to find (or access) a FSX benchmark, but unless someone can post one that shows conclusively otherwise, I think your best choice here will still be AMD unless you don't mind being at the very top of your budget or stretching it a little in order to afford an i5-2300 or better.
In the absence of clarity, I am going to assume you have, or are planning to get, a single 1920x1080 monitor. At that resolution, your graphics card should be a 1GB GTX460 or HD6850. If you are at 1366x768 with no upgrade plans, a HD5670 would be sufficient.
^that's a great price. If available to you, ignore the rest of this message. Otherwise, rather than post a build that would be very similar, start with this month's $500 SBM build, but whether or not you plan to overclock, add an aftermarket CPU cooler to it; your ears will thank you. If you don't mind spending a little more money, upgrade the CPU to a 955BE.
Again, if you can get that Microcenter deal on an i5-2400, getting that and an 1155 mobo would be a better way to go.