I think this whole "look, 10 years on and I'm still using the same computer" thing is being assumed to show the design excellence of the RiscPC a little too seriously.
Yes, the fact you can still get life out of it and find it useful today is fantastic. But, there's no particular reason why someone can't say the same about a Windows PC or a Mac of similar vintage - if it does what you want and still goes, fanastic, but the same can be applied to all platforms to some degree.
I guess the only difference is that application designers for RISC OS have been forced to work withing the contrains of old hardware, so you're more likely to find apps that still run great on your RiscPC. And lets face it, people in the RISC OS market have always been noted for writing lean code, so if anyone's going to be up to the task it's them.
But you also lose a lot. As an owner of an old Mac I wish I had a machine capable of playing modern games, being fast enough to get decent performance out modern multimedia apps.
The computer market is screwed up on a speed lust, thanks to the marketing division of the syrius cybernetics corporation^w^w^w^wIntel. Otherwise most people would be happy with older hardware.
So the fact that you're running 10 year old hardware really says nothing, other than Acorn went tits up and I'm happy to stick where I am. The point is that other platforms have progressed and that allows for some new fun and interesting applications. But for a lot of people they'd be fine with older hardware too, running that period software.
I think you're right to celebrate the birthday of the RiscPC, a fine machine. But, don't act all high and mighty because Acorn died and there was nothing to replace your machine with for years.