Tories will get over 30% of the vote. Everyone else under 20% - the small parties will have their vote split unevenly between them.
UKIP will, disappointingly for them, get fewer seats than last time - their attempt to capitalise on expenses-gate was only a short-lived success, partly undermined by their own expenses scandals on historical record.
The Greens will gain a seat or two because their anti-BNP tactical voting campaign has been (undeservedly) successful.
The Lib Dems aren't likely to make much progress; they're doing okay but the last Euro-election was at the height of their anti-Iraq-war movement exploitation madness and it'll be impossible for them to build on that, although the seats will probably shift around a bit to reflect the change in their support base.
The BNP will be lucky to get a single seat, I doubt it will happen (and hope it won't) but they won't get more than that (although it's not like we'd be the first country to elect a fascist into the European Parliament - in fact we may be the last!). A lot of the people who reckon they intend to vote BNP just aren't going to bother turning up to the polling station. The blitz of anti-BNP advertising was just a dogwhistle tactical wheeze by Labour...
No idea what will happen to the Labour vote, too many crazy things have happened in the past 48 hours but they will be in third if not fourth place.