The most lively action, at least here in Holland seems to be in the Commodore side, both 64 and Amiga. (specially looking at prices)
Looking at ebay trends it looks confirmed this is not a holland-only thing.
We have just seen an Amiga 4000T make 3000 euro (remember: 200 or so of these machines exist). About a year ago I've seen a CDTV II go for 2400 or so (6 machines).
Compare it to a very very rare prototype Atari 1450XLD sold recently, this made 3000 US$ (only 3 known to exist, IIRC)
Second could very well be the Falcon, they are also wanted.
Third might be Lynx (atari), I have seen some cracy prices on rare games.