How many seats will Labor lose? Who would like to nominate the NEW Coalition seats? Should we have a prize of a bottle of Red for the member who gets the sums right? And who will be the new leader of the ALP after the poll?
Red? Yes please!

Federally, I think it's hard to say, as the show-down between the miners & the Spokesparty for Dirt against Labor is still playing out. Once we have a better idea about whose side the majority of the public agrees with, then we'll have a better idea of the seats in play in Qld, SA and WA. A worst case scenario would suggest the loss of possibly 12 seats in states that the media and the miners assert that the RSPT puts at risk (Hasluck, Perth and Brand in WA, Kingston, Makin, Hindmarsh and Wakefield in SA and Leichhardt, Dawson, Flynn, Longman and Forde in Qld). This gives the Lib/Nats 75 seats, in which case they only need two more seats for an outright majority. Robertson on the NSW Central Coast provides an easy target, and this is just one example.
All this is of course assuming that the RSPT is having the resonance in the electorate that the media, the miners and the Libs insist it is. There has been some evidence to suggest that this is not the case, such as the polls showing high levels of uncertainty about the tax, and in the case of Qld, only a slim majority opposing, for all the hyperbole and even outright lies by the anti-tax brigade.
My opinion, (for what it's worth) is that the LNP will make gains in WA but little elsewhere. Apart from that, I think that Robertson on the Central Coast a la Belinda Neal, is all but a lost cause.
And against the grain of the current media narrative I think that Labor and/or the Greens will increase their vote significantly in small "l" liberal seats like North Sydney, Bennelong and maybe (here's hoping

) Warringah in NSW and seats like Higgins and Kooyong in Vic. They won't win enough votes (with the exception of Bennelong obviously) to win any of these seats, but they will become marginal seats.
As for a prediction as to the number of seats... I have no idea! I think the election is too far away at this point in time to make an educated guess. Might as well try and guess how many grains of sand there are on Bondi Beach.