A new list of the 500 most powerful computers has been posted by top500.org. NEC can still boast the most powerful computer by a massive margin.
IBM+HP make up a big chunk of the top 50. Sun made big inroads over the last 6 months thanks to the SunFire F15K (up from 37 entries to 88;or a decent 17.6% market share in numbers). I have tipped theregister.co.uk - let's see if my first tip ever to them makes it through.