Searched to see if this was already posted but it was expired and the price has changed... by 1p! Thought it was worth posting again as I think its a great deal, says 955 in stock!
OCZ 4GB (2x2GB) DDR2 800Mhz/PC2-6400 GOLD XTC Memory Kit CL5(5-5-5-18)
As part of OCZ's Gold series, the PC2-6400 2GB modules deliver the performance and speed gamers require for today's graphic-intensive DirectX 10 PC games. At 800MHz, the 2GB Gold Edition runs at 5-5-5 latency timings and offers unprecedented stability on the latest AMD and Intel platforms. As a Vista up-grader, the PC2-6400 4GB dual channel kit will provide maximum memory bandwidth and deliver the best possible gaming and productivity on Vista systems.