Hi, A friend of mine wants some help putting together a new P4 system. Can someone explain what's the latest with the P4s? There seems to be different types - s423 s478 and Northwood. Which one to go for? Also what's a good P4 mobo? I've always thought Asus were the best, but it's been a year or so since I last looked at these things. Thanks. Darren.