Id highly recommend the Diago Powerstation.
I was using a Rocktron DC On Tap (£35), but there was a LOT of hiss. It was all down to the buffered pedals I was using ie. the Boss ones, and even with them taken out there was noise due to powering pedals in front of the amp and in the loop at the same time.
I decided to splash out on a Diago (£69) and I have the quietest signal chain ever. Even running everything in the above post.
A Voodoo Labs Pedal Power 2 would be the ideal solution, especially as you can combine 2 outputs to create 18v to run the OCD, but as its £200 and can only power up to 8 pedals I went for the Diago. (powers up to 30)
Heres a nice guide to power supplies. Its made by Diago showing alternatives to their product, but its pretty usefull:
http://www.diago.co.uk/pedal-power/alternatives/