Depends on what you are looking for...

Powder?
Terrain?
Groomers?
Midwest Backcountry?
Good bar with a ski hill?
Cheap tickets?

Drive 8 hours more and go to Bridger Bowl in Bozeman MT......I've driven out there many times in one 16 hour drive (Bismarck is half way) and then skied four days and drove back in one day.  Split it up with multiple drivers and it is a piece of cake.  

They are having an awesome snow season....you may never come back!  :-)

Don't come out to Bridger Bowl if you're as you say, "...just looking for someplace with longer, intermediate to advanced intermediate in mind."  We have primarily advanced terrain here in Bozeman.  

You'd be better suited spending your time driving up the Shore to Lutsen or driving East to the U.P.  Michigan has a great offering of long-ish runs that are groomed daily at a level that's perfect for an intermediate skiier. 

If you want to take a real ski trip to Montana you'd probably enjoy The Big Mountain in Whitefish, MT or Moonlight Basin, just south of Bozeman.  These two are definitely more than 8 hours from Duluth but offer true Rocky Mountain skiing.

Just up at Bohemia.  5 hours total drive.  The Keweenaw is a really interesting place.  The skiing is the best in the Midwest for sure, however it is a bit scratchy right now.  Hanging in Houghton and Calumet is well worth the trip however.

Duluth should dedicate one snowstorm day a year as Lake Avenue ski day.  Close the street from top to bottom, let the skiers and boarders make runs to the bottom, warm up at Luce and ride a bus back to the top.  That would get us on the map!  Sorry that's a little off-topic Jen.

@Gary, didn't they do that once?  Or maybe it was for sledding, I forget.  But I seem to recall that people said it just wasn't fast enough for some reason.

So, I'm assuming we're all talking about downhill.

Lutsen has nice, long intermediate runs, but they usually have icy snow and sugar (an icee!!) as does Giant's Ridge when it's not complete slush.  Both places do a decent job grooming, which helps.  With fresh snow, both places tend to have it heavy and wet, which is nowhere near as fun as dry powder.

Well, that's where we live :^)  I agree with others that driving west and making a mini-vacation out of it is worth it if you are big into skiing.  But then you have to pay for gas, blah blah...