Premise landing pages is a really neat tool made by Copyblogger media and offers a bunch of neat features. Not only do they offer basic landing pages, but they offer things like membership creation (restrict content to members) as well as integration with BBPress and vBulletin to create users & login to the forums via oAuth. They now also support a bunch of different payment gateways so you can accept payments right through the plugin.
Before the release of version 2.4 it was a challenge to add membership support (restrict content) to custom post types. Now, it’s easy: