Which Quarter should i start in? and which one will have the most potential items for me?
No offense but a question this simple can be answered on wowhead. I don't think you need us to look up loot tables for you.
As for where to "start" I would say wherever your group wants to start. I don't think you should drag 9 other people around based solely on what wing offers YOU the most loot upgrades. THat's a bit selfish don't you think?
The simple answer is start with Spider Wing because that will both get you some gear and is the simplest of the wings. From there its either deathknight or plague. If you are going for plague make sure your group has watched the heigen dance video.