Studio XPS 9100 vs custom build?

[invinciblegamer1]

I'm trying to build a nice gaming pc for about $1200. I just saw a Studio XPS 9100 for $800 though.
Here's the link:
http://www.dell.com/us/p/studio-xps-9100/pd?refid=studio-xps-9100&baynote_bnrank=1&baynote_irrank=0&~ck=baynoteSearch&dgc=CJ&cid=24471&lid=561081&acd=10550055-249294-996511842

Should I buy that build, or would I be able to build one for even cheaper than that? I've been trying for a $1200 build with the new i7 processor and a decent amount of RAM, like at least 8 or 12GB. I know this XPS build has 6, but I might just upgrade after buying it. If those features are still pricy, (because I've heard pretty much all builds made by manufacturers themselves are 100% of the time more expensive than they have to be) should I continue to shoot for my $1200 build?
If I do shoot for that build, what components should I get?

So far I want to get something along the i7 series of processors, at least 1TB ddr3 hard drive, and a good graphics card. I haven't gotten very far deciding what I want yet, though, since this is my first build. I'm hoping not to get ripped off. Can anyone help me, please?

 

[Outlander_04]

The $800 model does not have a gaming graphics card

Even the other models have at best a middle to lower range graphics card

So head for newegg
and price
a 2500K
a z68 motherboard
2 x4 gig of 1.5 volt 1600 Mhz RAM
a case you like
a 650 watt power supply
windows 7 64 bit oem
a dvd drive
a hard drive

and spend the rest of your budget on the best graphics card you can find a 6950 , or 560 ti probably