This build of mine has gone through many iterations, but with the help of my other Guardian buddies (thanks to Toe/Music/Leon/Zöe), I have come up with an extremely powerful strategy. If you want to be able to do pretty much anything in game and never die, try this build out and see what you think.
Let's start with some general notes about my build and how it can be used. I will go through each of the traits and the reasoning behind them. Finally I will explain the pros and cons of the build and where potential weaknesses may lie....although I cannot remember the last time I actually died with this build.

What is an Immortal Guardian?
As some of you already know, calling a Guardian immortal is a bit redundant. They are an incredibly powerful class right now. The build I outline below is going to focus on how to create synergy with all the various Guardian traits, skills, and virtues. My goal is to be as efficient as possible when it comes to mitigating incoming damage, healing lost HP and keeping Boons up 24/7.
This type of Guardian is meant to work in a group/zerg environment, and synergizes particularly well with a Shout Warrior (this build will be coming soon), but it also does very well for solo farming of mats in Orr. If you recall from my previous posts, I recommended you find a buddy to farm Orr with to help whenyou get swarmed by a bunch of CCing Risen. That recommendation does not apply to the Immortal Guardian. Like the honey badger, my Guardian don't give a shit.
The Build
There is nothing particularly powerful about it in and of itself. When you combine it with a specific set of gear and runes though, you become unstoppable.
Valor (Toughness): 20 Points
Toughness/defence mitigates all direct damage, but does not help against condition damage (bleeds/burning/etc.). If you want to create a character that self-heals efficiently, then investing in toughness is a must. The standard rule of WvW seems to be that you need a minimum of 2,000 toughness/defence. My build and gear set gives 3,100+ toughness/defence. This combined with Signet of Judgement (10% reduced direct damage), makes it possible to simply regen through the majority of hits my Guardian takes.
Purity (V): Removes a condition every 10 seconds.
Guardians have low HP, so high condition builds can wreak havok on you if you don't have this.
Honorable Shield (IX): +90 Toughness when wielding a shield and reduces cooldown on shield skills by 20%.
Shield 4 gives you a cone aoe protection boon and Shield 5 gives you a bubble (also functions as a knockback/interrupt) that you can detonate for a direct heal. At level 80 with Exotic Cleric's gear, it heals everyone around me for 1,551 HP. Using the Shield 5 skill can be annoying for some people. If your team has pulled all of the mobs into a tight group, your bubble can knock them all over the place. You will have to make a judgement call. If your entire team is low on HP, it may be worth it to sacrifice aoe dps and heal everyone. You can always pull them back into a ball by using GreatSword 5 skill on swap.
NOTE: A lot of people prefer Focus over Shield on their Guardians. This is fine if you do more solo play. The focus provides more survival (blocks) and a bit more DPS. What you lose is a pretty big Direct AOE Heal, CC with the knockback, and Cone AoE Protection boons for the team.
Utility Skills (6,7,8,9,0)
6. Signet of Resolve (40 sec cooldown)
This heals for nearly 10,000 HP on my Guardian. That, along with the passive condition removal makes the choice easy.
7. Signet of Judgement
I use this for the -10% damage passive and that's it. It can be swapped out with other skills as needed.
OR
7. "Stand Your Gound!" (30 sec cooldown)
If you are going to be fighting an enemy with knockdown, this can save your life and the life of your team.
OR
7. Wall of Reflection (40 sec cooldown)
This is the wall I was referring to that becomes placeable if you trait for it. It is deadly against any form of range, be it WvW or Dungeons.
8. "Hold The Line!" (35 sec cooldown)
You should be spamming this in most groups. Also remember, the healing granted from this regen is calculated off YOUR +Healing. That's why it is so important for Guardians to focus on that stat if they want to support a team.
9. "Save Yourselves!" (60 sec cooldown)
This gives you a ton of awesome stuff. If you gear for Boon duration, each of the boons from this will last for 18 seconds and that duration will stack with any existing boons (such as the ones form "Hold The Line!").
0. Renewed Focus (90 sec cooldown)
This elite works great with my "OH SHIT" rotation. Other than that it doesn't do much. It's nice to have when you need it though.
OR
0. Tome of Wrath (180 sec cooldown)
Popping this and hitting 4 and then 1 will greatly boost your groups DPS. You take a very significant hit to your survival rate though, as you lose all regens and healing abilities.
Armor, Weapons, and Runes OH MY
This part isn't terribly complicated. Get Cleric's (Pow/Tough/Healing) armor,weapons, and jewelry. Remember, this build is all about efficiency, so while having more Vitality from gear (Carrion) instead of Toughness may help you against burst damage, it will be harder for your regens to keep up with the damage since you have less armor to mitigate it.
Runes are where it gets interesting. Use 2x runes from 3 different runesets and the Boon Duration bonuses add together. No idea if that is working as intended, but who cares. That. Is. Awesome. And. I. Really. Like. Periods. There are more runesets that have similar boon bonuses to those below; these are just the ones I chose because they are cheap and "free" (with dungeon runs) and I am so very poor.
- 2x Major Rune of Sanctuary from HOTW vendor in Lion's Arch for 30 tokens each.
- 2x Superior Rune of the Monk from AC vendor in Lion's Arch for 120 tokens each.
- 2x Superior Rune of Water from Trading Post for ~40 Silver each.
Overview
So what can you do with a Guardian using the above build? Anything. I used to swap between various builds for WvW vs. Dungeons vs. Farming Orr, but not anymore. This build works in every scenario. There are a few Utility skills I swap around (such as "Retreat!" instead of "Hold the Line!" when farming Orr for perma sprint), but nothing that requires me to change gear sets or trait builds. Below are the Pros/Cons of a guardian with the above build.
Pros:
- Nearly permanent Protection (33% damage reduction) for you and allies.
- Nearly permanent Regen Boon for you and your allies + Permanent Regen from Virtue of resolve.
- Nearly permanent Retaliation boon.
- Over 3,100 Armor while wielding a shield.
- Great CC through the use of the Hammer 4 skill and the Shield 5 bubble when used properly.
- Groups love you. Even if you are terrible.
Cons:
- Low HP (14k on my Guardian). Being burst/knocked down is about the only way you can die with this build.
- Lack of teleport abilities.
- Lack of good Direct heals. You have a few, but they are not as strong as a Warriors.
- Not as simple to play as Warriors, but not as complicated as an Elementalist or Mesmer.
- No burst damage. You do very nice damage, but it is very steady. Hard to catch people off guard in WvW.
NOTE: When I first switched to a Guardian from a Warrior, I died A LOT. My Warrior had nearly double the HP of my Guardian, and it took me a while to figure out how to play him properly. Don't forget to dodge, use your virtues and your elite. Once you get the hang of it you will become one of the most annoying people to try and kill.

That pretty much covers my Guardian strategy. I use a similar style for my Warrior build and it works incredibly well with my friends Guardians. That guide will be coming soon.
See yall in game!