So Star Wars has been added to Marvel's Digital Comics Unlimited subscription service. And it's got not just the classic Marvel comics, but a lot of the Dark Horse comics (although I didn't spot any Dark Horse logos on them). I've gone and split them into a "reading order" that follows a chronological order.

KNIGHTS OF THE OLD REPUBLIC
Star Wars: Knights Of The Old Republic (2006 - 2010)
Star Wars: Knights Of The Old Republic - War (2012)

PRELUDE TO WAR
Star Wars (1998 - 2002)

THE PHANTOM MENACE
Star Wars (1998 - 2002)

THE CALM BEFORE THE STORM
Star Wars (1998 - 2002)

REVENGE OF THE SITH
Star Wars: Purge (2005)
Star Wars: Dark Times (2006 - 2010)
Star Wars: Dark Times - Blue Harvest (2009)
Star Wars: Darth Vader And The Lost Command (2011)
Star Wars: Dark Times - Out Of The Wilderness (2011 - 2012)
Star Wars: Darth Vader And The Ghost Prison (2012)
Star Wars: Dark Times - Fire Carrier (2013)
Star Wars: Dark Times - A Spark Remains (2013)
Star Wars: Darth Vader And The Ninth Assassin (2013)
Star Wars: Darth Vader And The Cry Of Shadows (2013 - 2014)

THE DARK TIMES
Star Wars: Agent Of The Empire - Iron Eclipse (2011 - 2012)
Star Wars: Boba Fett (1997)
Star Wars: Boba Fett - Enemy Of The Empire (1999)
Star Wars: Blood Ties - Boba Fett Is Dead (2012)

A NEW HOPE
Star Wars (2013 - 2014)
Star Wars (1977 - 1986)*
Star Wars Annual (1979 - 1983)*
Star Wars: Vader'S Quest (1999)
Star Wars: Boba Fett - Overkill (2006)

EMPIRE STRIKES BACK
Star Wars (1977 - 1986)*
Star Wars Annual (1979 - 1983)*
Star Wars: Shadows Of The Empire (1996)

RETURN OF THE JEDI
Star Wars (1977 - 1986)*
Star Wars Annual (1979 - 1983)*
Star Wars: X-Wing Rogue Leader (2005)

NEW GALACTIC REPUBLIC ERA
Star Wars: Boba Fett - Agent Of Doom (2000)
Star Wars: X-Wing Rogue Squadron Special (1995)
Star Wars: X-Wing Rogue Squadron (1995 - 1998)
Star Wars: Shadows Of The Empire - Evolution (1998)
Star Wars: Boba Fett - Twin Engines Of Destruction (1997)
Star Wars: Heir To The Empire (1995 - 1996)
Star Wars: Dark Force Rising (1997)
Star Wars: The Last Command (1997 - 1998)
Star Wars: Dark Empire (1991 - 1992)
Star Wars: Dark Empire Ii (1994 - 1995)
Star Wars: Boba Fett - Bounty On Bar-Kooda (1995)
Star Wars: Boba Fett - When The Fat Lady Swings (1996)
Star Wars: Boba Fett - Murder Most Foul (1997)
Star Wars: Empire'S End (1995)
Star Wars: Crimson Empire (1997 - 1998)
Star Wars: Crimson Empire Ii - Council Of Blood (1998 - 1999)
Star Wars: Crimson Empire Iii - Empire Lost (2011 - 2012)

THE NEW JEDI ORDER ERA
Star Wars: Chewbacca (2000)

LEGACY ERA
Star Wars: Legacy (2006 - 2010)
Star Wars: Legacy - War (2010 - 2011)
Star Wars: Legacy (2013 - 2014)

N-CANON
Star Wars: Tag & Bink Are Dead (2001)*
Star Wars: Tag & Bink Ii (2006)*

* May not fit in with the canon of the rest of the comics.

I've started with the chronological start (I don't know if it's the best place to start) and I'm only the first issue in but it looks to be classic Star Wars so far. I expect in another couple of months we may start getting the new Marvel series, but in the mean time there's a lot of comics (500 issues I believe) to read.