really? $600? that's it? i honestly thought it would cost alot more than that. i've talked to a few people, and i was told that in order to get a decent, ok kind of PC that runs smooth, but not the best, it would cost about $700 - $800. that's insane
Note that:
a) this is just the price for the "backbone" of your PC. The cpu, motherboard, ram and videocard. Those 4 components are the most important components for any gamer.

these prices are just an indication. you didn't say in which country you live, so we can only guess.
c) I have no idea about taxes in the US. what I've seen so far is that if something is $100 without taxes in the US, it costs 100 euros with taxes in my country.
d) check an online webshop (like Newegg.com) for exact prices.
The point is: you can build your own PC. You can even upgrade components individually. Although you have to upgrade cpu+motherboard+ram at the same time. There are requirements that might not allow you to upgrade other parts separately, but we can't say without more info. E.g. if you upgrade your videocard, there's a 99% chance you'll need to have a proper PSU immediately. You can't upgrade your videocard if your old motherboard doesn't have a PCI-E slot. Etc. That's why I mentioned those 5 components first. The other ones (monitor, mouse, keyboard, dvd, even HDD) can be upgraded later.
I might have estimated prices a little too low.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=-1&isNodeId=1&Description=i5-3570k+3.4ghz
The i5-3750k (which is 210 euro in my country, including taxes) is $239 on Newegg.com.
I thought it was shipping for $220 2 weeks ago.
$50 for PSU? Are you crazy? You cant find any decent brands at decent wattages for $50
OK, you're right.
I found the Cooler Master GX-Lite 600W for 50 euros. But most 550W-700W cost up to 70 euros. Some people do like to exaggerate about PSUs, and think only 1 brand makes decent ones, and that you always need a 900W cpu for a regular system.
Also the total is more looking to be about $700+. You undervalues the motherboard, and need to include tax and any applicable shipping.
Buying anything but the cheapest Z77 motherboard (of a decent brand) is a waste of money for most people. An ASRock Z77 Pro3 costs 95 euros. An ASRock Z77 Extreme-6 costs 175 euros. For the regular gamer (non-SLI/CF, no extreme overclocking) the Extreme-6 has no real benefits at all. So yes, for 95 euros you can have a decent motherboard.
Hard drive can indeed effect performance. They can greatly effect loading speeds, and since Skyrim needs to load things on the fly in the world, stutter lag can be noticed if your hard drive is having to call up information.
The OP is on a budget.
Yes, buying a SSD would improve loading times. (I got one myself).
But if you want to invest your limited budget in a smart way, it's much better to spend that extra $100 on a faster videocard+regular HDD, than on a slower videocard+SSD.
And again, the $700 is only an indication for cpu+mobo+ram+videocard+psu. A $200 videocard is the cheapest videocard I would recommend to any gamer. For exact prices: check your preferred local webshop.
The whole point is:
a) you can buy your own system, and save a lot of money on prices of components

you might be able to reuse some components from your old PC (monitor especially)
c) it doesn't need to be as expensive as some people will make you believe.