Cheers Pete.
Something else that rather put me off the Mac was that there was someone in the Apple Store complaining that she was on her fifth iPod in two years - something (mainly the hard drive) had failed on them all. It made me wonder if Apple/Mac is a triumph of style over substance, although OSX does seem to be a good version of Linux.
(I also wondered why she didn't buy a different brand of MP3 player.
)
I had wi-fi problems with my Acer 5612 running Ubuntu 8.04 - the signal strength fluctuated a lot and was sometimes lost. Although, to be fair, this is at some distance from the router - a floor up and through two solid walls and a floor full of copper pipes.
I made a parabolic reflector for the router aerial, and that made a big difference with the Asus eee PC (also running Ubuntu 8.04) but it didn't help much with the Acer laptop.
So... I did a clean install of the latest Ubuntu 8.10 on the laptop, without expecting too much, but actually it has improved things a lot - the reception is much more stable and hasn't (yet) dropped out.
I'll probably stick with it and stop thinking that the grass is greener....