Xander's paperclips are meticulously sorted. This is because he stole them from Willow.

Anya's are also meticulously sorted. This is because they are still in the box. She owns paperclips because humans do, but she still hasn't quite worked out what they're for.

Spike's paperclips are meticulously sorted as well. He stole them from Xander.

Giles' paperclips are meticulously sorted too, because he confiscated them from Spike after he found him straightening them out and sticking them into a voodoo doll of Angel.

Willow's paperclips are meticulously sorted because she imitates Giles.