Thanks all for the input. So far, I'm not hearing a lot of compelling (for me) reasons to go with a custom build:
1) It is fun to choose your own components and put together your own rig (I can live without this, especially if something goes wrong with the rig)
2) You can OC a custom built rig (N/A since I don't plan to OC)
3) Building your own rig allows you to "stick it to" to the big companies (N/A for me since I care most about price/performance ratio instead of making a political statement)
4) You can upgrade a custom rig easier (N/A for me since I typically only upgrade the video card before doing a completely new system build/purchase)
On the other hand, going with a Dell gets you:
1) Free technical support and no headaches ensuring the system works out of the box
2) A quiet gaming rig (unlike the jet engine I have now)
3) Perks, like a flat screen monitor included for free
All of the above said, what REALLY matters to me is price/performance ratio.
If I can build a rig for less than the equivalent performance I will get from a Dell, I will go the custom route.
However, if I can get a Dell with equivalent performance and an equal or better price to a custom rig, I will go with the Dell.
I was thinking along similar lines to bamacre:
I have built plenty of systems, but my next PC will definitely be a dell from their Outlet.
Something like this...
http://www.majortoker.com/images/dell_xps410_769.jpg
... but I'll switch the video card out myself for an 8800 GTS.
Would you be able to build a custom rig with an 8800GTS at a similar price point?