Well what is it you want the computer to do for you?
FWIW, the problem with most tier one vendors is that they often use non-standard parts. One of the most common things to die on a computer is the power supply. With a "white box" computer you can just go to the corner computer store and pick up a replacement. Dells (or HP or for that matter Apple) typically have custom power supplies.
Now I realize you don't think you have the knowledge or skills to build a computer, but for the most part it really isn't that difficult to do as long as you have basic instruction following skills.
My personal recommendation would be to go to a white box vendor, that assembles a computer out of standard parts. They are typically only a little more expensive than putting the pieces together, offer tech support and will test things out for you after the computer is assembled.
We bought a couple of computers from this place for my job and have been happy with the results.
http://www.cyberpowerpc.com/
IME, consumer tech support from most tier one vendors (dell, HP, etc..) sucks horribly. You are almost invariably dealing with a drone in India, who is only permitted to run you through a script and has no ability to actually problem solve. I would only consider buying one, if I got one of their business machines, since then you would be talking to their business tech support. Which understands that you have a brain and they can actually be helpful.
