How much do you think this rig is worth? 2008 Gaming rig.

yeah $400 sounds just about right

I get $287 when I add up the parts.

Case: $35
CPU: $35
Mobo: $40
Cooler: $20 (keep it and sell it with stock cooler at stock speed since it's only a 7% OC)
Graphics: $55
HDD: $25
PSU: $35 (haven't heard of Arctic, so I don't trust it)
RAM: $25 (2x1GB sticks is as good or better than 1GB + 2GB = 3GB)
DVD: $17

Does it come with a legal copy of Windows XP or anything pre-installed? That could help sell it.

You'd do best selling it on ebay. You might pull $400 for it there.

I know the things here are second hand, but a most of them prices I've got to ignore. Did you just pull them prices out of the air?

The graphics cards were worth £300 ($488) only a few years ago, and you're pricing them at 11% of that 3 years on? - rediculous. Both cards are the 512MB versions and come with coolers still costing £25 new. You can get a 8600GTS on ebay for around £35, so add on £15 for each cooler and that's got to be worth £100 ($162 USD) today, not $55.

There is 3x 1GB sticks RAM installed, and all will be sold with this machine as it's a noticeable improvement having the last stick in.

You've never heard of Arctic? You must have.. you've just not noticed the name. They make CPU coolers, VGA coolers, thermal paste, case fans and power supplies. They also make mice, keyboards, headphones and loads of little things. You've never heard of say the Arctic freezer pro (which is on this forum a crap load)? Or Arctic MX-2 thermal paste? What about the Accelero XTREME VGA coolers?

Nothing pre-installed.

Sorry dalauder, maybe everything in California is dirt cheap, but I've never seen second hand prices fall that low here.

They may have been $488 three years ago but things have changed since then and you can now get single cards that are at least 4x or more powerful for $100 - $150. Plus 3 years old means there is no warranty and the reason most manufacturers warranty GPUs for less than 3 years is that is pretty much the average lifespan of them -- Even Factory refurbished cards that would be closer to new than used are selling for around $50 on Ebay so $55 - $75 is about right for 2 3 year used models.

You have to realize that prices on systems have come way down from 3 years ago and performance has gone way up --- for $400 you can build a brand new system that is much more powerful than the one you are selling. For examples just look over the system builders marathon articles to see what you can get for $400 - $500 ! For example this setup from last septembers article for $400 (and many prices have dropped even further since last september ) :

Right now, Tiger Direct has a 9800GT for $50 new. That equals the performance of your two cards with a single card with a warranty. So I suppose I should drop the value of your cards to $45. I'm sorry, but obsolete hardware isn't worth much.

The prices I suggest are about what you can expect on Tom's Hardware. You'd get more money on ebay because people don't know what they're buying.

Case: $55 gets you a new Antec 300 Illusion with free shipping. I'm betting your case isn't as good and I can't give more than 75% of cost for used items--$35.
Mobo: Almost impossible to quantify. New AM2 boards are $40, but they're not ASUS. On the other hand, it's obsolete hardware so who would pay more than $50 for it?
CPU: You get much better peformance with a $60 Athon II x2 CPU. Used it should go for $45. Yours deserves less than $35, I was being generous.
Cooler: You didn't say what it was, so I'll assume its a little worse than a Hyper 212+, which goes for $29 new. I'll credit you with $20 used.
Graphics: $45
HDD: Samsung Spinpoint F3 1TB's are often $55. Seagates and Hitachis can get cheaper. These all have double the capacity and much better performance (aside from Barracuda 7200.11). I've recently seen new WD 500GB drives for $40, so I'll credit yours for $30, since failure is more likely with older drives. And this assumes your drive is SATA.
PSU: I've heard of Arctic--just not their PSU quailty. I assume they're no better than Cooler Master, which I'd never recommend. I'll up that to $50. I'd buy new myself.
RAM: I give away 2x1GB DDR2 for free, like I said. And 1x2GB + 1x2GB is no better. But it is 800 speed, which goes for too much online now to be worth buying. You can look at online prices for these legacy items and assume it's worth $50. From a practical standpoint, I'm not gonna credit 2 sticks of DDR2 as worth more than DDR3. Considering 2x2GB DDR3 is regularly $25 after rebates and yours is worse than 2x1GB--I can't credit as worth more than $25.
Optical: new SATA DVD drives are regularly $17 on Newegg. If yours is IDE, then I should credit it for $10. SATA and I should credit it for $15. I'll assume SATA.

This new and fully explained grand total is: $295
Although your parts would cost nearly $400 new today, they're used, out of warranty, and too obsolete to be worth a purchase--sorry.

This would get thoroughly handled by a new $400 computer. That said, try to sell it on ebay for $400. Maybe start it at $200 with $20 shipping and see how high it goes. I wouldn't be surprised if it doesn't go high though, considering that most people who know how to install operating systems know how to find what a computer is worth. So you really should include a pre-installed legal copy of Windows.

Okay, I realise that the components split up aren't worth that much.. but if I look around for what pre-built computer you can get for £250 ($400) you're talking about a dual core (sometimes a quad) with 2GB RAM and no graphics card. Sometimes they have a basic ATI 3xxxx or something similar included, so for a pre-build computer it's obviously worth plenty more than the components themselves.

I'll pop it on ebay and see what interest is there, but as I know it's still powerful enough for most lite gamers want so if no one bites I'll keep it as my faff-around machine.

Thanks for your input anyway peoples.

Not many people that can install Windows are that opposed to putting compents together themselves. If you've got a copy of Windows XP around that you can pre-install, that seriously increases the value of your system and broadens who it appeals to significantly.