I'm genuinely worried about the Senate, actually. The Coalition probably won't get a majority, but the more I look at the polling, the preference flows, and Antony Green's calculator, the more I fear the balance of power won't be held by the Greens but by a ragtag bunch of largely right-wing independents.
The following parties, in my estimation, are all in the running to hold seats in the Senate:
Greens - duh. Six of their Senators are only halfway through their terms; three are up for re-election. Sarah Hanson-Young is facing an uphill battle in SA due to poor preference flows. Scott Ludlam might have a bit of a challenge too. Peter Whish-Wilson will be fine in Tasmania. Not sure if they can make any gains anywhere - Victoria is a good chance. A second in Tasmania is unlikely, though they'll stay in the count for a good while.
Katter's Australian Party - look a good chance to pick up a Queensland seat.
Australian Fishing and Lifestyle Party - will stay in the race for a while in Queensland due to good preferencing flows; probably can't get over the line but they're a dark horse.
Family First - have favourable preferences in Victoria, Queensland, and Tasmania.
Shooters and Fishers - definitely in contention for NSW's final seat.
One Nation - disturbingly likely to actually get that final NSW seat.
Sex Party - were looking good to challenge for Victoria's final seat until a cabal of right-wing micro-parties failed to register preferences in time. I don't think they will scrape over the line now.
Wikileaks - were also looking to challenge for Victoria's final seat but I think they have faded now, especially after their serious fragmentation over preferences.
Nick Xenophon Group - he's got one SA seat wrapped up. Can he repeat his state feat and poll well enough to bring a friend? Surely not.
Australian First Nations Party - very possible to get a Northern Territory seat. The ALP are currently just above a quota, but their support has slipped in the Territory; if it slips below a quota, even by half a percent, First Nations will be in because EVERYBODY is preferencing them above the ALP. This is pretty much the first time the Territory's had a meaningful contest for the Senate.
(Plus the DLP's John Madigan will still be rocking around as he's only halfway through his term.)
You see what I mean? My estimation is that the Greens will win 2 seats nationally (so down 1 for a total of 8), Xenophon will retain his SA seat, One Nation will win in NSW, Katter's candidate will win in Queensland, and Family First will possibly win 1 somewhere. Too tough to call the Territory race, so let's leave it out. That would be a crossbench of 13 Senators when you add the DLP. The Coalition should remain around their current tally of 34, give or take one. That means to pass legislation they will just need to court four or five Senators - allowing them to cut out the Greens entirely. Most of the rest of the crossbench are on the right, and some like Pauline are totally crazy. This could lead to ugly legislation.