Thanks all for the info. Now that I know it can be changed later, i'm not as concerned. I talked with a higher level bard on the server last night and was told that he and his guild started with coldain, killed giants to get on dragon faction, did HoT, then killed dragons to get on Giant faction and did Kael :p
So i've started killing the ice giants in Iceclad for now. They are decent experience at level 30 (2% a pop, sometimes 3%). Even though it does take a while to chant-kite them down with only one chant :p
Noticed i've killed maybe 20 or so giants so far and my faction HAS dropped, but still not KOS yet.