You may find it beneficial purchasing your computer hardware from a local computer shop. This can be a little more expensive when compared to the on-line retailers but the benefit is that if you do have any problems, there is usually someone just around the corner who can come out to help you.
However, we have also found that DELL (http://www.dell.co.uk) usually provide very reliable computers at very reasonable prices and they also have a comprehensive range of Customer Support options too (which we highly recommend).
We’d be happy to hear from you about any experiences/recommendations you may have when it comes to purchasing hardware. Please feel free to post here.