My friend and I have the original guild wars and are looking to get one of the expansions but are unsure of which to get, knowing its been about 5 years lol. We aren't much of PvP players, mostly in it for the story, monsters, and raiding places part. We really like the armor nightfall has to offer but unsure about the story and vise versa on factions. Eye of the north is an option but since its not on steam we didn't really look into it that much. So please give me some advice on which game to get and the pros and cons of them. thanks 

Ive just started playing this game and i am also very interested in this question.
Mind you i havent played PVP so i have no idea whats that is like

As someone who enjoyed it but never got deep into it I can only tell you that Nightfall and Factions are essentially "more Guild Wars" except set in a different culture. They are technically better in some ways that previous installments but its mainly down to preference for cultural style and extra class's. Eye of the North isnt a new culture and instead more of a "continuation" in terms of your current character where it provides a new "end game" of sorts with high level dungeons/armour/loot etc.

While someone is is/was really into Guild Wars might know better than me, I would admit I dont know much, I would recommended getting Nightfall or Factions for PvE players. I have never heard anything great about the story, at least above what any other "mmo" would provide, so I would choose based almost purely on cultural preference. Sorry I cant be of more help since this is most likely information you already know.

I'd recommend either Nightfall or Eye of the North if you don't plan to do PvP.  Heroes are a big boost, especially when/if you have a single friend you play with (between the two of you, you can customize the whole party's skills).  Nightfall has real story to it, if that's what you're after, that's long and meaty.  Eye of the North focuses more on dungeon crawling, with less story but more monsters, and they tend to be stronger monsters too.  Eye of the North also lets you have the Hall of Heroes, and tends to make plat faster (getting through a dungeon often earns three plat, after all the items are sold and the quest reward is claimed).  Nightfall has actual extra classes, which can be a bonus if you like variety.

Factions isn't a bad game, but it felt kinda short to me.  There are things to like about it, but I felt like I was fighting the same kind of enemies the entire game.  It also had a shortage of real late-game content.

In short, Nightfall for story, Eye of the North for raiding.