David,
Everybody has their favourite, but mine is Portsmouth-Caen...
1] Its a great run down to Le-Mans
2] Loads of great cars all heading the sameway at the same time... in '00 we had a 'convoy' of over 50 cars, from Ferrari's to Fords...(If you can call it a convoy at that speed!)
3] Another key point is getting out after the race (everyone seems to ignore this until they've experienced it once or twice!), and Caen is good in this respect... you can get out of the Le-Mans area pretty quickly (in Le-Mans 24 Hr terms anyway)
4] Finally, the locals come out, set up deck chairs by the road side and wave the cars by... truly fantastic atmosphere...
Neil