Thank you all for your comments & advice! Really appreciate it.
At the moment I use an old Intel Pentium M IBM Thinkpad T43 (1.86GHz) upgraded to 1.5GB RAM and a 17' Dell LCD screen for display, since the IBM screen is poor IMO.
Since I've still a relative newbie, I'm still only using Canon's DPP and Zoombrowser. I'm also still working out what photo workflow software package/s are best for me, so that doesn't really help you all in terms of what the best platform is most suitable
I friend of mine is a big Apple fan and suggested a MacBook but isn't probably thinking of my increasing need for photo editing capabilities. He always mentions the stable nature of the hardware & Os which I like the sound of. My patience is severely tested by Windows error messages and crashing software (this may be a symptom of my old machine tho).
I'll also admit that I like their styling and first impressions of the OS interface.
Only considering Apple notebooks, it looks like the 13' MB is not going to be sufficient for my needs and I should increase the budget for a 15' MBP at least. Other than Apple, I'll also investigate the cost of DD_nVidia's suggestions.
Thanks again for the help everyone!