Well, currently, the Mclaren holds the record at 242mph. There is a video and audio file avaible... (390, 391..................391..............392!........ ....thats all she'll do, 392 km/h....still mighty impressive isnt it?).
The Veyron is promising a top speed of 406km/h (252mph), but, that remains to be seen still.
The Koneiggsegg CC promises at 220+mph top speed, but, Ive not heard of this being independently verified as of yet.