Good gaming PC's are almost always waaaaay overpriced for what they are, the best gaming rigs tend to be ones you build yourself however they are nowhere near as cheap as they used to be especialy if you do not already possess a copy of windows as it's rather expensive.
Cheapest way to do a decent rig is to buy a fairly decent OEM and bang in a new gfx card however this can void your warranty so should anything fail you might be in trouble if you don't know what you are doing.
The rig i'm using atm is one i built and kept fairly updated, however money constraints over the last 2 years have let it slip quite a bit. The specs are:
Intel Q6600 Currently stock
Gigabyte P-35C (I think) MB
4GB OCZ Gold RAM
ATI4850 (It came overclocked as standard with a little switch on the back that overclocks it further should you need)
a REALLY old Creative soundcard (It's old but it still beats the crap out of onboard sound)
750W PSU (Cant remember make but it has modular cabling and solid output)
Some old DVD-RW i've had ages
A pretty standard logitech multimedia keyboard, only cost like £10 and feels better than my stepdads that cost £100
Logitech G700 Gaming mouse (This thing is fantastic i never thought wireless mice could be soo responsive but this thing is crazy accurate and has lots of buttons you can map)
For monitors i have a 22" Samsung that atm needs repair, a Gateway FPD2185W 21" (using this one right now) and i also use a 32" Acer TV which i intend to replace as the resolution is now too low.
The most important question is what is your budget? and 2ndly what do you expect out of it?
Seeing as I suck on comps, I dont know the name of the thing I have.
But it is a fairly good gaming laptop, a Packardbell. Cost around 800€, not sure about the exact price, since I bought a lot of gaming equipment to go with it.
I used to do tech support for packard bell in the UK and they used some awefull cheapass equipment back then and i doubt it's changed much since then.