dude, i have the msi k9a platinum board, and i couldn't be happier. there are tons of options for overclocking, and voltages are really easy to do, and they go up in normal increments, and also have a percentage increase so you can really pinpoint a specific voltage if one is too high. also its a stellar board and is really nicely layed out.
also phenomenal choice going with the 3850, i have one with some aftermarket cooling and it runs like a dream. runs every game that i want to play on maxed settings with only a tiny bit of lag at certain points. except crysis.
also speaking from experience the 520hx is what i have for a psu and it runs awesomely, very quiet. also its modular so you can cut down on the amount of cables you have and you can 'customize" what you have for connectors so you don't have as many connectors flopping around with nothing to do. also if you can get it get a 7200.11 500GB drive, they are really big, enough to store about everything that you would need unless you are doing tons of videos + pictures + music + extra stuff.
on top of that, you might consider a 4000+ x2 for your cpu, its cheaper and i've oc'ed mine to 3 but it wasn't 100% stable, but its 100% stable at 2.95 and i only dropped either 65 or 85 on it, so if you are really concerned about the overall cost of your rig, you can drop some serious cash on the cpu.
and to the poster who was wondering about temp differences between the mx-2 thermal "pad" and the paste, the paste itself makes it run about 1-2C cooler, but there isn't that much of a difference, and saves you 6 bucks + shipping for the paste.