You'll need to go some to beat a Reserator 2 - it's a VERY effective water cooler. It's as good as 2 Reserator 1's in series. Also have a google for "Alphacool Cape Cora 10" and "Preytek Serenity" as these are well-regarded alternative passive cooling systems. The Preytek is about to become available in the UK as a full kit for half the price of the Reserator 2 and it has proper water cooling components in the kit that you can upgrade with (it uses proper 3/8ths tubing for a start although it also uses G1/4 threads so you could make it 1/2" tubing if you wanted).
The AquaComputer PC-G70 triple radiator is available for about £235 if I recall correctly and the place that sells them will build it up properly with a Laing DDC pump and EK, Danger Den or Swiftech blocks for about another £100, so it's not cheap, but there will be very little that you couldn't cool with that set-up.