This is the post organizing the various relationships Erza has with people who are in Luceti. If you feel that Erza's opinion of your character deserves mention, post a comment and I'll see what I can do!
Updated 11/1/2011
Legend
+++++: Erza greatly admires you to the point where you're like a member of Fairy Tail to her. Given how tightly-knit the guild is, this means a lot
++++: you're a good friend of Erza's
+++: she likes you, but isn't entirely sure about you yet
++: an acquaintence of Erza's, you get along well with her
+: she doesn't really know that much about you to get an opinion, but she's okay with you
x: you irritate her slightly
xx: a major pest, but not much more
xxx: Erza actively dislikes you
xxxx: she hates you, which in general is cause for alarm
xxxxx: the best suggestion if Erza sees you would be to run. Run for your life.
Canon Characters in Luceti
Natsu Dragneel: +++++ (Natsu's habit of challenging, among others, her to fights at random, along with his sheer stupidity, frustrate Erza to no end. However, she acts as a mother figure to Natsu, and the two become incredibly angry if they see either one in pain. Their bond is among the thickest of the Fairy Tail members, and when he was taken out of Luceti, she felt worse than she had in a while)
People She Met in Luceti
Adell: +++++ (one of the first people Erza met in Luceti. She quickly noticed similarities between him and some of her guildmates back home, and the two recognized how powerful the other was. The two share a strong trust, as exemplified when Adell admitted his demonic heritage to her, and now as a member of the Blue Rogues, she will make sure not to let him down)
Aku: xxx (a massive ham, and an extremely loud evil overlord. Aku believes that he is the lord and master of everyone in Luceti, or at least, that he will be. In addition, Erza was forced to retreat from him when it became clear that her powers had no effect. Formerly in Luceti)
Estelle: +++ (a young woman who's certainly enthusiastic when it comes to books, she helped Erza find some new works of literature, and set up Luceti's book club, which Erza has taken an interest in. She certainly seems nice from the few interactions that Erza has had with her)
Knives: xxxxx (with a demeanor like that and an ominous-sounding name, Erza automatically dislikes this man. Though, in her eyes, he's a somewhat stereotypical villain (she fights people who claim they will destroy humanity for some vague reason every other week), but she still considers him an extremely dangerous threat if left unchecked. Formerly in Luceti)
Mitsuru Kirijo: ++++ (Erza quickly found that Mitsuru reminded her of herself - serious, with little tolerance for rule-breakers, and they even look similar. Mitsuru quickly became one of her close friends in Luceti Formerly in Luceti)
Monkey D. Luffy: ++++ (though Luffy is immature, his care for his nakama shines through, despite what Smoker has to say about pirates in general. After all, someone who treasures their friends to the point that he does can't be bad, right?)
Smoker: ++++ (Smoker is quite dependable, which is always a good thing in Erza's mind. He acts as somewhat of a sobering presence, which has stopped Erza from (among other things) going after people like Yuber on her own. Their shared love of justice helps a lot)
Suberbi Squalo: ++++ (though she finds Squalo fairly obnoxious, especially when he's yelling, she'd find it hard to picture Luceti without him. The two have formed an odd friendship, and even though Squalo doesn't remember what he went through last time that he was in Luceti, she still considers herself his friend)
Canon Characters Not in Luceti
Lucy Heartfilia: +++++ (Lucy is one of the newest members of the guild, and Erza warmed up to her almost immediately. Like Gray and Natsu, Erza spends a lot of time in Lucy's apartment, even if they entered without her knowledge. As the two are the only constant female members of their team, they have had a lot of time to bond, even if Lucy is still confused by some of Erza's eccentricities)
Gray Fullbuster: +++++ (although his habits of stripping at inopportune moments (in other words, all of the time) irritate Erza, Gray is one of her best friends, having been so since childhood. Erza is the only one who can keep Natsu and Gray in line, and she is one of the few who can stop their arguing. Of their team, Gray is the one who Erza depends on the most, given Natsu's impulsiveness, Lucy's tendency to overreact to what Erza sees as minor inconveniences, and Happy's age)
Happy: +++++ (as Happy is Natsu's primary mode of transportation and keeps him from throwing up whenever they go on trips, Erza is grateful to Happy for his service to the guild. Also, the little cat has quite a bit of determination, coming back from a savage beating at the hands of the Oracion Seis' leader, and he is one of the few members of the guild that Erza does not actively discipline.)
Makarov: +++++ (the respect that Erza and Makarov have for each other is mutual. Erza holds Makarov in high regard, as he is the leader of the guild and treats them all like his children. Meanwhile, Makarov considers Erza the closest thing he has to a successor, if not for her habit of leaving the areas where she completes missions in utter ruin.)
Mirajane: +++++ (although Mirajane was Erza's former rival, the two get along well now. As she is one of the most loyal guildmembers, often putting her life on the line by disguising as other members of the guild to act as a decoy, Erza trusts her. Ever since the alleged death of Mirajane's sister, Mira became more meek and mild, and they dropped their rivalry, leaving no bad blood between the two)
Jubia Loxar: ++++ (as a former enemy of the guild, Erza can never be too careful around Jubia. Her infatuation with Gray and longing for acceptance has raised her in Erza's books, as she has not done anything suspicious since joining the guild. As well, she sacrificed herself rather than being forced to hurt one of her fellow guildmembers. Nonetheless, these are only deeds Erza has heard about; she has yet to see Jubia's loyalty to the guild with her own eyes)
Gerard Fernandez: +++ (although Erza wants to see him redeemed some day, Gerard tried to sacrifice her to revive an ancient evil mage, murdered one of her friends in cold blood, and forced her childhood friends to slave away at building a massive tower. If his amnesia keeps up and he can be turned to the side of good, she may truly accept him as one of her friends again. Assisting in the destruction of Nirvana helped, but it was just the first step)
Gazille Reitfox: ++ (similar to Jubia, Gazille was a former enemy of the guild. However, Gazille has yet to do anything to gain Erza's trust aside from assisting in the fight against Luxus. In addition, he disappears from time to time, not telling anyone where he goes off to. Only the trust of Makarov keeps him in Erza's good graces.)