Well, what ever happens today in Scotland, I think that Salmond has won: the concessions that have been offered Scotland by the leaders of the main parties in the UK are generous to say the least. In effect a no vote will trigger practically everything but independence and full financial autonomy, while a yes vote will lead to much protracted negotiations and to be honest I'm not sure either side in this has a good idea of how these will turn out.
The questions of economy, currency union and EU membership are academic to a point. Firstly Scotland's economy will probably do quite well, though the independence vote is not specifically about the economy but rather the right of a people to decide their own future - democratically. Currency union might well become a moot point - if Scotland enters a currency union with the UK pound then there isn't really much the UK could do about it; there are alternatives such as pegging a Scottish currency against the EU in much the same way as Montenegro has done. Even if Scotland's currency did devalue then this could be a good thing for inward investment.
EU membership is interesting, especially as Spain and quite probably Belgium has vested interests in quelling their own internal independence movements - even then the pressure from their local voters and even smaller EU nations which might feel threatened by over dominance by larger members might sway this. EU membership also solves the currency issue.
Border controls and the like? Well Scotland couldn't become a Schengen country unless the UK joined too and I strongly doubt that we'd see passport checks at any time in the future other than in the more fanciful predictions.
My main issue however is - regardless of yes or no - is what happens to Wales and to a smaller extend to Northern Ireland and England. Certainly some Welsh politicians seem blissfully unaware or even naive of the implications. Even the Conservative Party in Wales has come out much more in favour of devolution of powers to Wales than Labour.
Politicians always has vested interests anyway: the Conservatives know that their only chance of any power in Wales is through the Senedd while Labour can always sit back and count on votes from their heartlands both in Wales and England. If Scotland leave, or even in Westminster is reorganised to solve the West Lothian Question this might change as Welsh MPs would have little influence even if they did vote on English specific legislations. There's an interesting discussion about this on the TrueWales web site in an article written by Rachel Banner (24 Jan 2012): The West Lothian Question.
Ironically it has been Welsh MPs who have probably made some of the most important decisions regarding England the UK: Nye Bevan and the NHS, Lloyd George and Home Rule (which unfortunately didn't come to pass due to World War 1) and even back to the Welsh advisors to Queen Elizabeth the First who promoted the idea of naval supremacy.
If we come back to what has been offered Scotland now and since the 1998 devolution votes one must seriously ask the question of why Scotland gets so much at the expense of the rest of the nations of the UK. I'm still unsure why every change to devolution in Wales requires a referendum such as that back in 2011 which granted Wales the power to make laws specific to the needs of the nation. Are politicians so weak and afraid of their decisions? Surely the populace voted those MPs into power to make such decisions for the good of the people and so they should take the responsibility themselves rather than pass it off to often under informed voters?
So on Friday, will Wales be offered DevoMax? I doubt it - no politician is that brave.