I think to some extent it depends on what price bracket you aim at with your home built. Try to equal or better the bulk shifters at the entry level and you're wasting your time. Look at the package deals like Dells Dimension 1100 @ £299 with 15" flat panel monitor & free carriage. Their bulk buying power gives them too much of an edge. If you're looking at a high end machine however, you have a chance as this is where they like to make money and haven't pared their margins to the bone.