If we've said it once, we've said it 1000 times: TUAW loves RapidWeaver. One of RapidWeaver's strengths is that it has an easy-to-use interface, but you can do some really, really powerful stuff with the program. Plus, the third-party network of plugins and themes is really, really top notch.
YourHead Software, which makes some of my favorite RapidWeaver add-ons, has just released a new plugin called Stacks, which ups the ante on what you can do with RapidWeaver, without even having to mess with any code.
Think of Stacks as a souped-up version of one of YourHead's other plugins, Blocks. Mat reviewed Blocks a couple of years ago and it remains one of the best RapidWeaver plugins around. Stacks takes the WYSIWYG drag-and-drop layout approach of Blocks, but adds support for fluid layouts (even if your theme has a variable width), nested objects, stacks within stacks, and more.
I've been using the Stacks beta for the last couple of weeks and I have to say that it has opened my eyes to some possibilities with RapidWeaver that I hadn't even considered before. Traditionally, creating a different layout for each page is time consuming unless you rely on snippets or go with basic designs. Because I like to use RapidWeaver to rapidly prototype sites, being able to build out various layouts extremely quickly saves me time.
As a demonstration, I created this page in about five minutes using Stacks, some graphics and Elixir's Twitter plugin for Stacks. That's another feature I like about Stacks -- there's an API -- so not only can advantageous users look at building their own elements for use in Stacks, RapidWeaver plugin and theme developers can look at using it too. Stacks can also use Loghound's excellent PlusKit so that you can embed Google Docs, other page types or elements and do lightboxing with your photos, all within Stacks.
Stacks is $19.95 and it requires RapidWeaver 4.2.1 or newer to work. You can try the demo (direct link to DMG) for free and access all the features; you're just limited to a certain number of items on each page.