As far as I know joining the EC is not an automatic entry into the EMU. I don't know one way or the other but I don't think the new joinees will be joining the EMU just yet. Entry into the EMU would need to be able to handle such entries without a major impact on the value of the currency so I would say it makes little difference. What I would do is buy half now and half nearer the time, that way you would get an good average and if things went down wouldn't lose out too much but if they went up you could get a bit extra without risking all of it.