Ever since the first computer enthusiasts started watercooling their PCs there have been designers attempting to create the perfect watercooler. Of course the defacto standard is the AIO combo with a detached radiator however there have been many different iterations over the years and some of them were pretty good. One of the first retail watercoolers that I remember was the Cooler Master Aquagate. It was a bit underpowered by most modern standards but was very innovative having a bay mounted pump/res/radiator unit in an aluminum box with built in fan controls and LED readout. Aquagate was an assembly style AIO meaning it could be expanded but also required you to assemble it during the install.

Cooler Master followed this up with an Aquagate Mini which I believe is the first true AIO cooler featuring a remote radiator and pump block combo directly over the CPU. Interestingly enough this was back in 2004.