Does anyone remember how a Power Mac used to be a power house of computing? Now it resembles something like a vase for flowers.
The PowerMac line ended in 2006, almost a decade ago. The fact you could use one as a flower vase proves the superior design - there aren't many computers that can be reused in such a way once they become obsolete!
If you want to use a Dell, I would advise to pick one from the "Business" line of products (Lattitude), instead of the "End-User" line (Precision).
Vostro, Latitude and Precision are the business line laptops (in increasing order of build quality / reliability). Inspiron, XPS and Alienware are the end-user / domestic lines (again in increasing order of build quality).
The UK isn't 240V, it is 230V. As previous commenters have stated, the tolerances are different in the UK and the EU, but they are all based around 230V now.
Why would you keep a 486 CPU on its own - surely the whole system would be more use if you went to the trouble of keeping the rest of the documentation?
Somehow I think the capture technology is more important for that use case than the display technology...