I'm generally a Shinkansen fan, but the Hokkaido Shinkansen is a bit sad. The cost is ridiculous and I doubt it's going to pay off even if/when they open it up all the way to Sapporo.

We're going to Hokkaido this summer, and I was trying hard to figure out a way to get the Hokkaido Shinkansen into the mix, but nope, it just makes no sense in terms of time or money. JAL's Yokoso Japan fares from Tokyo to anywhere in Hokkaido are Y10,800 a pop, or you can get Tokyo-Sapporo for ~Y5000 on Peach, Vanilla etc, flight time 1:30. The Hokkaido Shinkansen to Hakodate takes 4 hours and costs Y22,690, or almost 8 hours (!) and Y30,000 (!!) if you chug onward to Sapporo with current connections.

And it's hard to justify a rail pass either, since Hokkaido has the crappiest train network in Japan and you need your own wheels for most of the interesting bits. Even comparing against the JR Hokkaido/East pass at Y26,000 for 6 days, it's cheaper to fly JAL return (Y21600), and with a family of four the difference is enough to pay for the rental car for a good 3-4 days...!