I just exchanged my desktop Pc for a new HP notebook, cost £699 from john Lewis, runs Ms flt sim 2002 at the highest detail and perfectly fast enough graphic rate. Not the most high spec notebook but for the price I think not bad. And small enough to take away on stop overs.
Specs are:
1.5ghz
80GB hard drive
512 ram
14" bright screen
wireless etc...
Have not yet tried the 2004 flight sim, but then the 2002 version has everything I could need for the moment.