I personally prefer to play my Guardian in the supportive / defensive role. Been rolling with and getting used to this build here. I prefer the Runes of Earth, Cleric's Amulet with Soldier's Jewel, and Sigil of Water on staff and mace with leeching on the shield. Weaknesses though are your damage output is kinda crap, so personally only play when your queing as a group imo, with random pugs it can be annoying, got some low hp so high burst / lockdowns can be a pain. But its extremely amazing at node holding, I held keep last night for example when pvping with Chook, Triage, and Kali, for a long time til they rezzed and still didn't die, was about a 1v4 (Guardians for the win) and has great support both offensively and defensively.
http://gw2skills.net/editor/en/?fUA...akQQsHaUGtRXFcIA;TsAgzCto2xsjYH7Oudk7s2YsxOEA
Also, heres a build I personally like to play and think its fun for shits and gigs.
http://gw2skills.net/editor/en/?fUA...aVggVKi39wUgxMeVAiA;ToAA2Cto2xsjYH7Oudk7soYQB
http://gw2skills.net/editor/en/?fUA...akQQsHaUGtRXFcIA;TsAgzCto2xsjYH7Oudk7s2YsxOEA
Also, heres a build I personally like to play and think its fun for shits and gigs.
http://gw2skills.net/editor/en/?fUA...aVggVKi39wUgxMeVAiA;ToAA2Cto2xsjYH7Oudk7soYQB