The gap is closing in the polls and it's looking increasingly likely. The SNP (Scottish National Party, the main faction advocating for independence) have past form for gaining a lead at the very last minute, and there were reports of a surge in first time voter registrations which is likely mostly 'Yes' voters (the No campaign is a joke and has almost zero grassroots activist presence). In 2011 the SNP were so popular they basically broke the PR system in the Scottish devolved government and got an overall majority, which no one predicted. They're very popular and credible and are running a positive campaign. The trend is definitely towards yes. On the other hand the Quebec precedent is that people are more conservative on the day than polls suggest, and factors such as bad weather, a (convincing) last minute offer of increased devolution from Westminster, or a terrorist attack or big international crisis could tip it back to 'No'.
It'd have a huge impact on England and the rest of the UK, politically and economically. Whether that means England becomes more insular and conservative in reaction, or starts to properly reflect on and address the massive problems in the UK that have made a 'yes' vote possible in the first place, is anyone's guess. Most English people haven't really being paying attention so far. On ITV they screened "Love your garden with Alan Titchmarsh" instead of the first televised debate and the Conservative government have had their heads in the sand from day one. Now the 'Yes' camp is leading they're writing out a plan for increased powers to Scotland on the back of a napkin to try and keep us in.
No one really knows what will happen on the EU question - there's a lot of conjecture and off-the-cuff remarks from lots of people, but officially everyone's keeping quiet. The EU will want Scotland in one way or another eventually and Scotland will definitely want to stay in or join ASAP, but whether a one-off deal could be made to have some sort of continuity of membership and how long it would take Scotland to get in if not isn't sure. It would all have to be negotiated after a 'yes' vote. The UK clout in Europe belongs to the Westminster government which can twist arms at all levels of the EU to portray an independent Scotland as in a dire situation with regards to fast EU membership but the reality after a 'yes' vote could be quite different. On the one hand it would actually be in England's interest to advocate for Scotland in Europe (as it would benefit Scotland, which would in turn benefit England as our economies are connected and they need us to help pay off our portion of UK debt and so on), on the other hand a quick road to Scottish EU membership could set a precedent for other regions to separate from their countries and then easily join the EU which won't go down well with other big EU countries wanting to keep their regions (Catalonia in Spain is the prime example).
Interesting times! I can't actually vote, I've been down south too long so am no longer resident, but I'm going up to watch history happen (either way).