A lot of the PC criticisms in these ads may not necessarily apply to XP, but remember that there's still a huge number of Win9x users out there. I don't recall the exact number, but it's over 50%; that's why Microsoft mandated that the new .NET 2.0 platform must run on Win9x.
These ads are funny, but I think they'll resonate with a lot of Windows users whose machines are either obsolete or plagued with spyware and other useless software that seems to build up on every consumer Windows machine I've ever used. Whether that translates into a flood of new Windows switchers, well I doubt it, but it will at least make them feel bad.
I do think that Apple's software development has been firing on all cylinders for at least a couple of years now, whereas Microsoft's development has been unfocused for quite some time. In that sense, these ads may be closer to reality than any previous Mac ad campaign.
Why the New Mac Campaign will Fail