Power Computing have supplied me with two high spec. PC's for video editing, photo editing and publishing. The company built the computers, which include a substantial amount of internal hardware, and supplied monitors and keyboards etc. The staff are excellent at helping you to design computers to match your applications and are always quick to get back to you when you ask questions. In terms of technical advice and after sales support they are amazing.
The company was recommended to me ten years ago and I have no reservations in recommending them myself. The staff are friendly and knowledgeable, and the equipment the company sells is very reliable. The first PC I purchased from them ten years ago is still in use!