I'd look into a Dell, too. That way, any hardware or software issues have a dedicated support line for them to call, and it isn't you.
If you want to go the MicroCenter route, by all means do so. But remember, MicroCenter will pricematch Newegg's prices, albeit including any shipping charges Newegg imposes.
I just put together a cheapie system for my 70+ y.o. mother to replace an aging old single core AMD system I'd built for her a few years ago (Socket 754....so that's how old it is.)
I got an Intel e5300 (would have bought the 5200, but they were OOS....and the 5200/5300 is PLENTY fast!), an Asus P5KPL-CM motherboard, BFG LS450W power supply (about the cheapest quality ps they had in stock), Corsair Value RAM 2 x 2GB DDR2-667, the case you'd looked at above, one of the OEM Samsung 22X DVD-RW drives, and a Hitachi 500GB SATA drive, OEM. But I spent a tad over $300 without OS.....thankfully I just transferred her XP from the old HD in her old system to the new hd in her new system.
But, in the end, the Dell way is cheaper and will be easier to manage as Dell will be responsible for support.