Dell Inspiron vs home build ??

You can build your own for about the same $$$, and:
You will be able to include a discrete gaming videocard - much faster for games.
You will not have to deal with a boatload of bloatware/trialware loaded on your Dell from the factory.
You will have to be your own technical support.
You will likely have a more reliable computer for your efforts.

The problem comes when you want to install a good GPU in the DELL. You will find out that they shipped it with exactly the Power supply for your ordered configuration. On addition to the new GPU you are going to install you would need a new PSU as well.
People in here complain about how high a price you pay for a decent GPU on prebuilts as DELL, The simple reason is though, that you are paying for the PSU upgrade as well in most cases.

OEM's cut corners anywhere they can, especially with the PSU and RAM. Here's a build that's better in every way for less than $30 more than that Dell.

Antec Two Hundred Black ATX Mid Tower Computer Case - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Antec NEO ECO 400C 400W Continuous Power ATX12V 2.3 / EPS12V 80 PLUS Certified Active PFC Power Supply - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/ComboDealDetails.aspx?Ite... $69.94 (Case + PSU combo)

Just keep in mind that the PSU DOES NOT COME WITH A POWER CABLE. Most people have one from an old computer, but it's something to keep in mind.

AMD Phenom II X4 945 Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 95W Quad-Core Processor - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

ASUS M4A785TD-M EVO AM3 AMD 785G HDMI Micro ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/ComboDealDetails.aspx?Ite... $240.98 (CPU + motherboard combo)

G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Dual Channel Kit Desktop Memory Model F3-10666CL8D-4GBHK - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $94.99

SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $54.99

LG Black 24X DVD+R 8X DVD+RW 16X DVD+R DL 24X DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM SATA DVD Burner - Bulk - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $29.99

ASUS VH202T Black 20" 5ms Widescreen LCD Monitor 300 cd/m2 18000:1 Built in Speakers - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $139.99

Microsoft Windows 7 Home Premium 64-bit 1-Pack for System Builders - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $104.99

Total - $735.87

F Dell.