If you're in the UK, there's a liquid market in BBCs, C64s and similar on eBay. There are a few sellers who refurb them (e.g. new power supplies, cleaned up cases etc). You can easily adapt a BBC to use SCART too (the lead will cost about a fiver) and use it on a modern TV, if you don't fancy using a big old CUB monitor.
I hope that the RasberryPi will be a re-run of the BBC Micro, they could do a lot worse than bundle it with a modern version of BBC basic, which was very advanced for its time.
