Possibly a 2x512MB pair of OCZ PC3700EB memory, which I recall was £360 (when a "normal" 1GB set was around 1/3 the cost). That said, it was cracking memory, so probably not the worst, but maybe the least cost effective. I've not bought properly mental memory since then, I've got 16GB now, but it's Corsair value. I've got a rather illustrious history of poor value purchases come to think of it, various SCSI drives (back when SCSI was indeed the dog's), a £500 RAID card, a £400 Geforce3 (it came with 3D specs though, in 2000, before it's time much?) The true worst is probably a 2x256MB pair of Corsair PC4000. The price was extortionate, they didn't overclock for toffee (replaced with a cheapo set of A-Data PC4000 that overclocked to 320MHz for a fraction the price), and I should have bought a gig anyway! EDIT: I just recalled a better winner - A PowerVR 3Dx card, when I already had an nVidia Riva128. Parents bought a PC with the nVidia card in it, though nVidia had naff all publicity at that time, and all the cool kids had 3Dfx or PowerVR cards. Little did I know that the Riva128 blew all of them completely out of the water, and I wasted £180 (when I was 13, £180 being a gargantuan amount of money). I was able to play a few extra games because of the PowerVR card (ones which use PVR specific engines and didn't use D3D), sure, but for anything that could use Direct3D, the gap between them was hilarious.