sambowler

Adds a simple bar at the bottom of the site indicating that you’re working on a development version, so you don’t accidentally break the live site (as we’ve all done countless times).
This plugin uses James Padolsey’s wonderful <a href="http://enhance.qd-creative.co.uk/demos/pulse/" rel="nofollow ugc">jQuery Pulse</a> plugin.

Development Notice

Adds a simple bar at the bottom of the site indicating that you're working on a development version, so you don't accidentally break the liv …

Brett

Frontend Features: 
 – adds a toolbar to the bottom of WordPress pages that will show meaningful information that helps developers to create optimized WordPress sites. 
 – Info includes SQL queries, query vars, peak memory usage, and a filetrace.
Backend Features: 
 – Provides a very basic checklist with suggestions for development. 
 – Shows basic server stats and information 
 – phpInfo 
 – WP rewrite rules (coming soon)

Developer Toolbar

Adds easy to access data for developers, including a fixed toolbar to the bottom of pages that shows query data and memory usage among other data.

Development Notice vs Developer Toolbar