Most of the characters are not as easy to put in alignment buckets.

What is Robb Stark? Arya Stark? Jon Snow? Tyrion Lannister? Daenerys Targaryen?

That's one of the reasons GOT is so great:  complex characters. 

Samwell Tarly would be a Lawful Good, right?

I think so.

Jon Snow would have been Lawful Good too but it's unclear who he's actually loyal to.

I guess Ned Stark was Lawful Good.

Ned Stark is the ultimate Lawful Good:

Reddit comments:

http://reddit.com/r/gameofthrones/comments/1f68c1/season_3_game_of_thrones_alignment_chart/

http://reddit.com/r/gameofthrones/comments/2770xg/all_spoilerstheoryi_am_busy_making_a_alignment/

I wonder if GRRM chooses for death randomly from each alignment or if there is a discernible pattern .....

I've never seen any analysis that speaks to a pattern.

At least a dozen characters have almost died -- Tyrion several times now! -- but it all still seems random.

But killing Ned Stark so early in the story hurts more because he was so lawful good.

You'll notice that every character on the season 3 alignment chart is still alive as of s4e8.

Except Craster.

Calling Nate Silver!  

Using the 16 characters from s1e1 who have died, we see that they do span all alignments:

One of my favorite numbers for the show's casualties is: 16. That's the number of named characters alive and appearing in the first episode of the series who are dead by this point (4.08) in the show. 16. Just from the first episode! 20 if you count the 2 dead direwolves, Dany's dead horse Silver, and the already-dead-at-episode's-start Jon Arryn, who appears as a corpse at his funeral.

The 16 1.01 named characters who have died by 4.08: Lord Eddard Stark, King Robb Stark, Lady Catelyn Stark, Ser Rodrik Cassel, Jory Cassel, Maester Luwin, Septa Mordane, King Robert Baratheon, King Joffrey Baratheon, Khal Drogo, Viserys Targaryen, Qotho, Ros, Ser Waymar Royce, Will, and Gared.

Edit: A couple of people seem to be missing what this stat is saying; once again...these are named characters who are dead by 4.08 who were alive AND appearing in the series premiere, 1.01 "Winter is Coming". 16 characters from thefirst episode are dead by 4.08. The number of named characters total who have died in the series up to 4.08 is over 50.

...

Well, let's see. Named characters, alive and appearing in 1.01, who are still alive:

Jon Snow, Arya Stark, Sansa Stark, Bran Stark, Rickon Stark, Hodor, Theon Greyjoy, Daenerys Targaryen, Ser Jorah Mormont, Illyrio Mopatis, Tyrion Lannister, Jaime Lannister, Cersei Lannister, Sandor 'The Hound' Clegane, Tommen Baratheon, Myrcella Baratheon...with one undetermined life/death status in MIA Benjen Stark.

So named characters appearing in 1.01 who we know 100% are alive during the events of 4.08: 16. Benjen's status would shift it one way or the other, but otherwise we are at that 50/50 ratio.

Adding in the direwolves (which I did, along with Jon Arryn and Silver in my above post) brings it up to 20, so still 50/50.

More Reddit comments:

http://reddit.com/r/gameofthrones/comments/273sov/s4e8_an_awesome_little_detail_show_watchers_might/

New alignment chart for season 4:

http://pandawhale.com/post/46070/game-of-thrones-season-4-alignments

Here's alignments for game companies: http://pandawhale.com/post/20543/game-alignments