So I currently have three active roles in Rift. Let me give them to you, and you give me your two cents.
Solo/PvE Content
The idea: Basically the goal here is to let me get a hand in the game. Designed when we were running a full group, I found that for normal mobs, given casting times, I got in perhaps one hit before they were dead. Which is fine…but not fun. So I expanded and tuned the build I had used in Beta. It has one purpose really, and that is to provide as many instant cast spells as possible. As you can see, this fits the bill. Six instant cast damage dealers, and three melee strikes (also instant) provide the oomph. Group healing is minimal for standard content, and the instant cast Doctrines + Healing Breath work fine for that. With Luminous Gaze on, my crit chances are north of 20%.
Full On Healing Power
The idea: I had been using a Warden-central build to heal with, but after a particularly rough dungeon run, I decided I wanted a more traditional healing base rather than a HoT centered one. I came up with this. This build feels off to me. And I haven’t had a whole lot of chance to shake it down because I finished it right about the time the group stopped getting together. The ultimate goal is simply a character who does nothing but heals for dungeon runs. I just keep thinking there is a better way to do it.
The Farmer
The idea: This is my experimental build. Really it started out as a desire to have some AOE bombs to drop while still being primarily a healer. Then I thought maybe it would be good for farming low levels or whatever. Now it just seems useless. Mostly I’m at this point looking for how to get the best use out of the Cabalist soul and the Purifier soul. I really like them both, but I can’t seem to find a good way to get them working in my favor. I’m open to suggestions.
Also…please do me a small favor. Do not overuse hyperbole in your response. Often with build people like to use the words “always,” “never,” “must,” “require(d)(ment).” Spare me. I’m not a powergamer. Just tell me what its good for any why you like it. (-:
Harbinger Zero 
Interesting choices. Without going into details, I have a Tank role: Justicar/Druid/Inquisitor, lots of instant casts, good threat gen, the healing pet, and I can easily heal both myself and my fiancee in normal situations. As a rogue, she provides most of the DPS, however. I don’t solo with this character, I’ve never had to worry about serious DPS. I do have a AoE DPS role: Cabalist/Inquisitor/and some zero-point I can never remember. Pretty good multi-target DPS as well as single target DPS from the Inquisitor. My Healing role is *very* similar to yours: Sentinel/Purifier/Warden, though I’ve been told Warden is THE best healing soul in the current end-game. I have not verified this for myself, having just reached 39 yesterday. Overall, I am loving the cleric for my “Spousal Leveling Contract.” I never really tried tanking in previous games, and I have discovered that I really enjoy it, both as a duo and in groups. Cheers. 🙂