I had the manitou axcel fork on mine and swapped it out for a marzocchi. All i can say is that if you are getting the one with the manitou, thats where i'd upgrade. Go for a marzocchi or fox. Makes a considerable improvement in steering response and generally makes the bike feel lighter and better, plus it's air adjustable. The manitou has not adjustment that makes any noticable difference.
That and discs are the 2 main upgades i did to mine and thats all it needed as far as i'm concerned. Now it brakes and handles as well as i could want.