nvALT

nvALT is a fork of the original Notational Velocity with some additional features and interface modifications by Brett Terpstra and ElasticThreads.

NVALT ADDITIONAL FEATURES

Auto-pairing and selection wrapping for brackets and quotes ([],(),””,”)
Pin a note to the preview while editing other notes
Shortcut (CMD-Shift-L) for inserting [[Links]]
Better MultiMarkdown 3 support (if installed locally)
Right to Left support
External editor support improved
Simplenote Tag sync1
Textile and (Multi)Markdown support with Preview window (hold down Control to view temporarily)
HTML source code tab in the Preview window for fast copy/paste to blogs, etc.
Unique interface design changes
Customizable HTML and CSS files for the Preview window
Social note sharing via Peggd
Convert imported URLs to Markdown, and optionally strip excess content with Readability
Multi-note tagging with autocompletion
Full-screen mode (requires OS X 10.5 or higher)
Optional menubar and menubar-only modes
Color schemes
Black/White
Low-contrast
User customizable
Collapse/Expand notes list and search field
Improved readability with optional width limit and margins
Really cool scrollbars
Word Count (hold down Option to view temporarily)
Working localizations (French, German, Portuguese)