Every year for the last 23 years, the top computers around the world have been logged and charted on the world TOP 500 Super Computer list. Defined by their relative positions on the LINPACK Benchmark, the list provides an insight into the top hardware and systems around the world.
For many years, the Earth Simulator Center (Japan) has maintained the top spot, and is still there this year. Crucially, it is still a fair way off it's closest competitor (Lawrence Livermore National Laboratory). However, slashdot claims that a new IBM cluster (that is currently on the list in a in-complete setup) will knock the Earth Simulator of it's top spot when it is completed.
In terms of list statistics, 94% of the list's computers are located in the US, Intel chips run 57% (AMD 6.8%), yet the usage of Opteron chips saw a 7 fold increase. Interestingly, China and the UK snuck into the top 10 this year at 10 and 4 respectivly.