I honestly have no idea whether Scotland would succeed economically or not - for me it cannot be their prime motive for independence to say that they would be better off outside of the Union. By the same token London could do the same.
Much more problematic for the Union has been the political and social polarization over the last 30 years since the erosion of Britain's manufacturing base. England's blind acceptance of Thatcherism and its daughter `free market economics', concentration on lack of economic regulation and the building of service industries and the financial sector. All of this socially accompanied by an unparalleled strengthening of the divide between rich and poor. I do not believe, as some on here have stated, that Scotland has moved to the left but rather that the centre of English politics has moved to the right. A development also marked by a strengthening of Atlantic ties - if you doubt that then try to imagine Britain having engaged in something like the Iraq war during the 50s 60s or 70s - inconceivable. In short Scotland has become enstranged from the mainstream of English politics. But, the same could be said for North East England or Merseyside - can they break away as well ?
In the end the only valid reason for Scottish independence is that they were once a sovereign nation. The act of union in 1707 united England and Wales to a Scotland which (I am sorry to say this) was a nation in name only. It was a bilingual country separated into Highlands and Lowlands - populated by peoples who were unintelligable to each other, with a Celtic Gaelic speaking north built on clan loyalty and brigandage on the one hand, and an industrious English speaking south. Both sides being mutually antagonistic to each other. The lowlands supported the Union because they had more sympathy towards the English than to the clansmen of the north. The south, particularly Glasgow, profited greatly from the union because it opened up colonial trade to them. Glasgow increased it's population tenfold in the next hundred years. What I am saying is that Scotland only really became a country, with a common national consciousness, as a part of Great Britain. This is why I cannot accept the emotional appeals to Scotland's past - its use of symbols such as the bagpipes or the kilt (both of which were held in abhorrence by the lowlands in the not so distant past. The only thing which unites Scots is their present attitude to England and for me this is an insufficient basis to build a nation upon. Just in case our spud friend latches on to this post I should also say that my Mother was a Highlander (born in Kirriemuir, and growing up in Glen Clova) which makes me half English half Scottish - I don't want to be split in two because there's only one of me.