I think we could work around the $600 budget JCD. Give me a little while (crazy busy day) and I'll try to get something together. If we can get a decent mobo and cpu we can likely get you what you want (including salvaging your DVD drive & hard-drive) while giving you some room to upgrade in the future as well for about $600.

Alright, I came up with a couple of options that I thought might work.

It assumes that you'll be reusing your monitor and peripherals from your old computer.

 

Option 1- more of a kit (somewhere around $550 after rebates):

The barebones
A case and PSU

Windows

Optical Drive

You could reuse your DVD or get a different case/psu combo if you wanted.  I'm a little leery of the PSU in the combo if you later decide to get a big video card as an upgrade, but it should be fine with the kit mentioned.

 

Option 2 - more mix and match (about $625 after rebates):

Windows

Optical Drive

CPU/MOBO combo

RAM/GPU combo

PSU/Hard Drive combo

Case

With this option, you could reuse your old DVD to shave off $20 ish and buy a cheaper case (or get one locally) if you needed to cut down more.

 

Option 2 is generally better stuff - same mobo and CPU, but the video card is a good bit better and you get double the RAM.  You will have less HDD space, but it will be faster a faster HDD, and you could add in your old HDD one as a second drive if you need more space.   If you're planning on gaming with more modern 3D games (shooters and such), I'd think the extra money was worth it, and I believe that the GPU comes with a free copy of DIRT3 if that's your thing.

But if you're mainly building for something like Star Ruler, which is more CPU bound, both should be effectively equal, and it might be better to save a bit now, and then save up for a really good video card if you needed/wanted one later.  Plus option 2 has a lot of rebates, so your initial price will probably be more like 700 and you'll have to wait months to get the rebates back, which can be a pain.

Anyways, hope it gives some ideas if nothing else.

If you are gaming and going with SLi then you need POWER baby, lots of it. I recommend 850 Watts or better. Air flow through your RAM is important and you can get by with heat sinks built onto the RAM. I also recomment quad core processor. I'm using an Intel i960 quad core with 6 GB RAM with heat sinks and 850 Watt PSU. I'm not gaming but use a lot of video processing. I can render three bluray videos at once. Rendering takes about 70 mins

I just dont get it. Why is power so important (other than the obvious need of power for your computer)?

I doubt you need to worry about SLI or quad cores on a $600 total budget.  SLI starts getting in the picture if you're more willing to spend $1000 or more.  A quad core could be doable if you tossed in an extra 100, but I don't think it would often be a value buy with your budget.  I think for what you want, even for 3-4 years down the road a single GPU will do fine, maybe with an upgrade thrown in there on just the vid card if you really get into higher powered games.

In general getting a good PSU is more important than most beginning builders think.  Yes, for the power draw, but cheap/ bad power supplies (that may not give the sort of power that they claim to at all temperatures, like when your computer is running a game and heats up) can also cause a lot of errors - crashes, bluescreens, failure to boot, and in bad cases can even send surges through your electronics if they get really overloaded, or start to die and brownout after a few years - meaning you have to buy another one and go through the grief of reinstalling it, diagnosing the problem, and possibly replace other bits if you have a really bad failure.

But you don't need to have a HUGE wattage PSU, and PSU's with 700-800-1200 watts aren't necessarily well built.  There are PSU calculators that let you know about what you'll need when planning a build, and generally they err on the safe side since they don't know if you're buying a cheap PSU that the manufacturer lies a bit when they tell you its wattage, or a quality one that gives you the real numbers.  Its kind of an area you have to ask someone or research a lot if you really care about it, or expect to have a really big need for power.

Remember when I said back on page 2 (how in my opinion) I didn't think you were ready to build your own PC.  What you need to do first is either take a basic computer hardware course or get yourself some decent hardware books (failing that......a lot of googling and some serious web-based hardware guides) and not just asking question after question on forums.

It is extremely easy to mess up when building a system and (again in my opinion) forum posts are no replacement for a quick-n-dirty hardware course somewhere or even basic web guides from some of the respected hardware websites out there.  (check back over some of the links others have posted for you)

 

Google is your friend.........

 

 

Just to answer your question in simple terms.  Power is the single most important aspect to a system build.  By ensuring that each component receives all of the power it requires consistently one can avoid frustrating things like spontaneous system reboots and or  hardware-related freezes/bluescreens/crashes etc.

Many of the above issues I have been tasked by clients to investigate/solve were traced back to systems that had received upgraded hardware components over the years but upgrading the PSU was neglected (to the detriment of the entire system).

the monk is right... you should do more research and get familiar with the components..
But back to the PSU - 750 - 850 will do just fine if its an ( 80+ PSU ) even if its a sharkoon brand you will have enough puffer to build in a second graphics card in sli or crossfire ( IF YOUR NOT HAVING A 590GTX ) but since i think the 590 isnt for disscussion for your pc you would even do fine with a good 600Watt PSU  that also has 80+  I posted my neighbours PC a page ago...
example what you can do with a 1000 watt PSU you can run 2 way 590gtx with a ton of other plug and play things printer + led flash light + 5 harddrives  + external drives /---or 3 way sli 580GTX and thats just crazy... and a waste of money

While power output is important, all brands aren't created equal. No PSU lives forever, and the cheap, light ones tend to go out with a bang rather than a whimper.

If you don't know what brand to go with, the rule of thumb is "heavier is better", because that weight usually means bigger transformers and heatsinks.

 

Very true!

Pretty much what you get is what you pay for.  Computer components are not all the same.  As with anything, you'll pay a premium for 'quality'.... which is why you can spend $300+ for just a keyboard .... and probably yet get a mouse/keyboard combo FREE in your packet of Wheeties...;)

Very true !
But keep in mind to still google about your " pick " most of the capacitors and transformers n coils are made in china even if you get a mid class PSU its like getting yourself nike shoes all looks good but if you flip em it will say made in china NOT saying that this is bad they make some of the best  capacitors in the W
-but  it never hurts to take a short look at the PSU you want to buy via google mostly all of the good ones are tested and listed...
I would even say the PSU will be the hardest thing to pick in setting up your rig just because there is so many of them some good ´some bad n noisy others just very good thats why i mentioned looking in google or it magazines