I've read that Initiative Computing Elite 6.0 is very good but pricy at around £250-£600,
web-site:
www.flyelite.ch
Also good is Jeppesen FlightPro, its cheaper at around £100,
web-site:
www.flightpro.com
There is a review of both in issue 4 of PC Pilot,
Web-site:
www.pcpilot.net