Face it, most of us like the idea of having an HTPC (Home Theater PC) hooked up to our TV. The flexibility we get with an HTPC over just a DVD player or a gaming console is enough alone to justify the cost.  I have built a bunch of these for people and until recently, I have never used pre-built systems. There are many advantages to building a custom machine for your theater, but the biggest disadvantage is the cost. Lately, I have been using Small Form Factor (SFF) HP's and believe it or not... they make great HTPC's.