Pretty much it feels like a case of choosing whether you get stabbed or shot, either way it sucks. Last time loads of us(Brits) voted Lib dem and we get the tories by proxy? That just highlights how horrible our political system really is. If there was an option that said "none of these parties represent me or my beliefs" that would be what I would choose. As it stands I will be deciding who out of Labour and the Conservatives will do the least damage to the country and vote based on that. Not that they really have to follow through on anything they say to get in power it seems...
As far as Scotland goes, I think they should be free to make up their own minds. However it all seems very vague: there seems to be no indication on how trade with England would go, how borders would work, the currency used or trade with Europe. Admittedly I haven't followed this closely so I could well be mistaken but it seems to be based on a hell of a lot of assumptions. There are a hell of a lot of considerations to make basically outside of feeling patriotic and wanting independence.
Agreed on this point, it's an extremely flawed argument that Scotland is somehow leeching off the treasury. There's also reasonable evidence(although it appears to be debated) that Scotland actually contributes a great deal more than England economically to the point where the north sea oil fields are left out of some reports...