well, I used to build all my computers myself (well, I buy the parts and do the rest, not build the actual computer

) but over the last years I haven't paid much attention to all this chipset/mainboard/cpu stuff with incompatibilities and stuff (I remember on computer I had where the northgate/cpu/gpu combination was making constant trouble).
furthermore, I haven't made good experiences with the small shops in my area. most of the time, their knowledge wasn't superior to mine and they just did what I would have done myself when manufacturing the computer. so I ended up with a computer that was much too loud, and had wierd quirks. All Dell computers I've ever bought worked well and silent.
And I did look up local sellers and wrote down the computer of my desires. In the end it wasn't cheaper at all than my selected Dell Dimension 9200