I am doing a good guy run through and am morally on the fence about giants.

On one hand, it seems they kill horses and, judging by their loot, passersby on occasion.

On the other hand, they aren't aggressive unless they feel threatened. And they only seem to want to take care of their mammoths.

What do you guys think?

They kill people who intrude on their territory. Other than that, most of them are completely peaceful.

I say most, because there is a quest (The Cursed Tribe) where you will find hostile, potentially man-eating giants. Theyre the only ones though.

I only kill them if they try to attack me first or unless I am doing a bounty quest or other quest like "The Cursed Tribe" that requires that you slay one. In other words, I leave them alone unless they are causing trouble for me or someone else (as is the case with bounty quests).

I don't think that absolute good or evil is interesting, but personal codes of good vs. evil are. So my question for you is this:

Is your character a believer in innate evil? That there are humans/elves/beastfolk, and there are monsters? Is good/evil an innate part of who a person is?

Or does your character believe that everyone is doing the best they can, and whenever you can you champion those who are doing good? Is good/evil all about what you do, and anyone or thing can be good or evil?

If it's the former, then kill giants on sight. If it's the latter, only kill giants who you see performing evil acts.

I dont kill them unless i have to, dont see point to it.

Giants are the closest of the Mer Races to Nords. My characters do it for the right to buy property, or because Orcish Boots, Gauntlets, and Cuirass look good on certain characters. I have never killed a Giant just to collect Toes.

I have killed Giants for "failure" to thank My character for saving Mammoths from Dragons.

I had killed a Dragon, saved three Mammoths and a Giant, and another Giant attempted to send My character orbital for it

You really shouldn't. They tend to be a peaceful bunch, only protecting what's theirs.

I've noticed a strange issue with giants much like the dragon example you mentioned.

I was trying to help the giants and mammoths kill some bandits who were shooting at them and then when I killed a bandit with my bow the giants suddenly turned on me instead (and I never even hit a giant or mammoth at all). For their ungrateful attitude, I killed them off too.

All around good input guys! I am doing a defender of the people RP at the moment so it was important to know what giants are up to...it seems the majority feel they are peaceful and don't kill travelers hence my character would respect them and not interfere. Not that I was running out of things to do, plenty of bandits to take care of!

They'll fill a big soul gem. So will their pets.

I'm playing a moral. I kill giants but not mammoths. Not really sure I can support my reasoning. When I first entered Skyrim I avoiding killing anything that didn't really really ask for it. Now I'm on a one man aggrandize. I didn't used to kill the giants but I need their souls to power my weapons that will destroy a man like me who intends to ruin the world.

What I want to know is where are the female giants?

I had a random moment where I was walking along a path and a giant started running after me for no apparent reason! I had to kill him in the end, and I've just completed a quest (miscellaneous) where you have to kill a giant located somewhere not too far from Whiterun (I think) and the second giant attacked me when I did that so I had to kill both of them. I did actually feel bad about it, too!

On the whole though I stay away from them. I try not to get too close when passing them and they're fine.

I only kill giants closest to cities, towns and villages.

It has been suggested that Mammoths are actually female Giants. Another suggestion is even less palatable: female Giants die during childbirth. But a third explanation seems the most likely: Bethesda forgot.

Pretty much this. I'm willing to make an exception for the one in the camp in Eastmarch where the dead Khajiits are, because it seems like he has killed them - but even then, I only kill him after getting the bountyletter from Ulfric's steward (I like to RP that since it contradicts Brunwulf's statement that Ulfric doesn't care if someone attacks non-Nords in general and Khajiits in particular, it makes my characters wonder what really is true about what is said about Ulfric... ).

Most of my characters tend to leave 'em alone, no matter what the character's morality. The more amoral ones have better targets for their hostility, and the "good" ones feel that the giants leave them alone, so they should leave the giants alone. Even my alchemist assassin didn't target them, although the toes probably would have been helpful to her, for leveling purposes if nothing else.

I believe there was an official notice from the jarl posted outside that camp stating that the giants had the right to be there, and under no circumstances should anyone attempt to trade with them.

Khajiit were the ones who broke the rules here. Doesn't mean they deserved to die, but it isn't as cut-and-dry as it appears at first glance.

Giants are far more friendly to me than most of the denizens that inhabit Skyrim's 'civilized' towns/cities.

I feel bad killing giants. They're mostly peaceful, so I see no reason to be hostile to them. I remember one who has a camp very close to the road though, he's said to attack travellers. I know they're intruding on his territory, but civilization, progress and all that - I ended up kiling him to protect the civilians.

They are sapient and non-hostile, therefore killing them is murder.

Well... My personal opinions of "Good and Evil" is this:

Good will help and protect others who requires it, and doesn't expect a reward.

Evil will only do things that benefits them and will do just about anything to get what they want.

Then Neutral are those who prefer to keep to themselves and live life day-by-day.

So... From my experience, Giants are Neutral creatures. They prefer to live within their camps and will only defend their homes if unwanted company gets too close. So, there is no reason to kill them if you are playing as a Good character.

Is attacking a giant a bad thing well it sure as hell aint smart if your a low level thats for sure.

Game wise though giants are neutral like most creatures.

This is the way I see it too.

That said, I'm not my characters. A few of my characters are cold-blooded murderers.

I've killed plenty, but it's definitely a bad thing to do. Always feel guilty. Mammoths maybe even more so.