I leapt from RISCOS to PCLInuxOS and was a little wary of doing so. However I have reconfigured my desktop to look like RISCOS (just for the familiarity) and as for the software, well, astonishing. It's all free.
I thought I would have all sorts of configuration issues and the need to eneter command line stuff but I had NONE. You can get PCLOS from a magazine disk (or download off the internet), boot up a laptop and "try before you buy" i.e. try before you install to harddisk.
I can honestly say that all the complaints I have had about RISCOS falling behind, lack of applications, multimedia etc etc have all been answered by the 100% free PCLOS.
There's no need to spend a fortune on a Macbook either. A dual core 17" laptop for sub £500 will do fine. If you really must you can always set it up to dual boot the dreaded resource hungry Vista, which I have but I only use it for commercial games!
FYI, for free:
OpenOffice - nuff said
Firefox - with all the plug-ins and extensions including the ability to play AVI's, Realplay etc. All sites with Micorosft nonsense work!
Digikam - (recent wow) an album organiser and photo editor
Gimp - extensive image editor
Amarok - music
Synaptic - what a dream of a software install and update application.
MySQL - relational database
Perl,Python etc etc - the choice is yours
VLC, MPlayer etc etc - a multitude of video players
Thunderbird - email
Games - loads of them.