Vintage computers are getting collectable. Have been for a while. Early Apples get good money if they come with original packaging. Apple Newtons are also worth money now. Acorns and BBC Micros are great for kids right up to year 10. They are simple, and with Basic, they get a great grasp of programming. (emulators work well too). Early PCs are worthless. CRT fishbowls are worthless. A working PC with some form of windows are great for kids doing IT VET, as this course if competency based, so they have to be able to pull one apart and rebuild it ... so if a local high school offers VET IT, then they could make use of an old PC, but doubt they'd want the monitor. Printers are worthless, especially as Colour Lasers are sub 500 these days.
It is a trend (and I have a friend in the UK who sells on eBay) to get an old machine and fit a mini-itx motherboard and redo to make a PC. The yanks like them a lot - they make great receptions toys. (
http://www.mini-itx.com/) - check out the mad toys and cigar box PCs...
Also 'Game and Watch' handhelds are highly collected, as are Atari Woodies...ROM games are collectable too - but you need the box to make them worth while.
Simon (MB Games) and Texas Instruments Speak and Spell - and Speak and Maths are getting good money now - but check the 'edition' later ones are not as well made or desirable. Early calculators are worth collecting, as are LED Watches.
The great thing about collecting vitage electronica - is that it's plentyful and affordable. As an IT teacher, I use old machines - as it makes kids think more - XP does everything on auto pilot, to the point that when it doesn't work, it's too hard for kids to problem solve, as they usually have no real idea of how it's working (or not).
Software for vintage micros is all over the internet, and if you do have kids in year 9/10 who are starting out, then using BASIC is a good idea as its a simple language to learn and then if/when they extend to something like Visual Basic - the favourite choice for HSC programming tasks, they will have a better entry point.
If you've got early VIC20's C64s, Game and Watch, Apple Classics, Speak and Spells or Atari Woodies, let me know ... and do check out the mini-itx site, there are some very cool projects ... it's not that hard to turn a toy VW into a PC!
(and Macs are better than PCs) - Massive clock speak = heat and limits the number of processes the CPU can do in any given cycle, which is why Macs run faster off lower clock speeds - horse power without torque is pointless.