How to Use this Handbook
This handbook is an organizational theme handbook plus my viewpoint on the general effectiveness of themes. The idea is to direct players to themes that serve specific goals. I looked at each theme and placed them into the following five categories:
Defender: Either provide immediate action attacks that resemble marks in behavior or they have adjacent range attacks that apply status effects that complicate the monster's next turn.
Striker: Do extra damage or do consistently more damage
Leader: Enable, buff, or heal without using up your immediate actions
Controller: Apply control effects from a distance
Non-standard: Doesn't really fit any of the above categories
I used the standard Gold/Sky Blue/Dark Blue/Black/Purple/Red color scheme.
Powers that were available as either alternate Utility or Encounter powers I only took into consideration if there was some fantastic element about them. Usually, any given class is going to have some better choices unless they're at a minimum Sky Blue or Gold(see Iron Wolf Warrior encounter attack powers or Sidhe Lord's Utility 2)
How should you pick themes on this basis? There are three basic ways:
If you want to enhance your general overall power, look at the themes rated Gold, Sky Blue, or possibly Dark Blue. Anything I've rated Gold or Sky Blue is likely going to be very useful, even if that's not your role.
If you want to enhance a particular role that your character does, look at the themes in that role. If you're a Defender who feels that they need to be a better Defender, pick a Defender theme. I'd recommend looking at anything Black or better. Be careful - if you're already really good at your role, you might want to consider something outside your role. If no one ever attacks a nearby ally, picking up a theme that relies on a nearby ally getting attacked isn't going to be Sky Blue even if I rated it such.
If you want to enhance your utility, look at the non-Standard themes - they often don't directly enhance a specific role, but rather give options, either in or out of combat.
Also, each theme lists whether or not weapon attacks are melee, close burst, or ranged, and whether or not the theme uses an implement.
I want to emphasize here - I think Color is generally more important than Role. A Sky Blue theme outside your role in many cases might make you more important to your party than a Dark Blue theme in your role.
It owes a lot to Who am I Really: A Theme Handbook by ls612.