Earlier this year, I posted an article listing my favorite plugins … now I’d like to cover some of the themes and plugins I consider particularly powerful.

What does it mean to say a plugin or theme is powerful? My definition is, a plugin or theme that surprises you because it stretches the bounds of what you thought WordPress was all about … a plugin or theme that forever banishes the question, “But I thought WordPress was just a blogging platform?” A powerful plugin or theme is, in other words, transformative. in that it potentially changes our concept of what WordPress is all about. I’ve mostly avoided highly specialized applications in the following (e.g., microblogging themes and specialized storefront themes), and gone instead for what I consider to be some (but certainly not all) of the best general-purpose addons that truly transform the WordPress experience. What themes and plugins would you add to the list?

Themes That Transform Your Site’s Structure

Many themes you’ll run across provide a pretty static structure for your site, possibly with a few canned variations. But a few options have appeared over the past few years that allow you to construct your site as though you were working with building blocks or grid paper. Other trends are “responsive” themes which automatically adjust their appearance to your device’s screen size (laptop, smart phone, pad, etc), and support for HTML5. Most of these themes come with a moderate to high learning curve … but then, power always comes with a price.

Builder – I’ve done several sites with this framework, including this one. Unlike Genesis, Builder comes with access to all its child themes and it provides true drag and drop construction of page layouts, and you can define multiple styles for a site. As is the case with most good things, it’s not free and comes with a learning curve. Builder isn’t currently (October 16, 2012) responsive but promises to go responsive with its next big release.

PageLines – Offering drag and drop layouts, this is a responsive theme that’s getting good reviews. Pricing is similar to Builder and Genesis.

SuperSkeleton – Another responsive theme that uses a flexible grid approach to layout construction. Pricing is on a per-site basis, so it might be a good choice for someone who’s doing a single site.

Genesis – I’ve done a couple of sites with this framework. Genesis provides many places where you can place widgets, but getting Genesis to jump through hoops often requires a bit of PHP programming. Unlike Builder, you have to pay for each child theme you buy. I’d say Genesis is a good  choice if you can find a child theme you like and don’t mind editing PHP. Builder might be a better choice if you plan on doing a bunch of sites for different people, and can live within the child themes’ constraints.

Lightspeed – Another theme that promises drag and drop construction of page layouts. Haven’t tried this one, so I can’t compare it with the others above … it’s licensed on a per-site basis so it might be worth evaluating if you’re just doing  a single site.

Market – A theme that’s focused on creating an online store. I wouldn’t say there are any fantastic solutions out there for a WordPress online store, but this one ain’t bad. The other alternative is purchasing an external e-commerce product and styling it so it looks like your site. I’d recommend steering clear of the WP e-Commerce plugin, by the way, for the reasons listed in the linked article.

Plugins That Transform Your Site’s Content

Probably the most powerful Content Management System (CMS) is Drupal, which lets you define and manage your own content types. By default, WordPress comes with two content types: Posts and Pages. Many plugins add additional types of Posts and Pages. There are a couple of plugins that let you extend WordPress in various ways, turning it into a full-fledged CMS. Note that both of these require some PHP programming to use. so if you’re not a PHP programmer and have an idea that they could help you with, you might consider hiring a WordPress developer who knows PHP to hand-roll a solution for you.

Pods – This will let you extend existing WordPress components like Posts, Pages, Media and User records by adding your own custom fields and functionality to them. You can also create whole new content types; I used Pods to create a Book Review content type for a client, for example. Pods is a donationware plugin.

Piklist – This is billed as a rapid development framework for WordPress. In effect, it lets you build your own plugins and widgets with their associated settings pages without hand-coding them (thus the rapid development part). It still requires PHP knowledge to implement, however. Piklist is freeware, and as of mid-October 2012 is still in Beta.

Plugins That Transform Your Visitors’ Experience

Here are some of my favorites … there are many others, so this list will provide you with a feel for the breadth and depth of the functionality that truly powerful plugins can bring to your site.

BuddyPress – Want a site that provides an online community for your group or your customers? BuddyPress can do it: activity streams like in Facebook, extended profiles, messaging, optionally enable separate blogs for users, and its own “ecosystem” of plugins and themes. BuddyPress is a free plugin. Note: if you’re going to use BuddyPress, I suggest committing to it from the start … deleting it from your site once it’s installed can be a bit of a hassle.

s2Member - Set up different membership levels with access to different content, integrate with various payment gateways for paid memberships. Unlike some of the other solutions out there, s2Member is a free plugin.

WPTouch - Adds a custom theme for mobile devices (mobile phones, tablets). Very customizable. Notes: There are special tricks for setting this plugin up to work with caching plugins; there’s a free version, but you need the paid version to get support for iPads.

bbPress - Adds full-featured user forums to your site. Integrates seamlessly with WordPress (and with BuddyPress, if you use it). From the folks who brought you WordPress. Free plugin.

Gravity Forms - The most powerful form-creation software out there. User entries are stored in the database and mailed; you can easily set up multi-column and multi-page forms. Integrates with some mail list programs and payment gateways. Paid plugin.

Events Manager - Full-featured manager that lets you set up events and let users book time, purchase tickets, etc. Integrates well with BuddyPress as well as WordPress. Free plugin, but a few features (payment, custom booking forms, coupons) require the Pro version.