Sublime Text
Pros:
Sleek interface
Great colour themes
Autocompletion
Goto anything
Multiple selection
Split editing
Cross platform
Trial
Cons:
Expensive
TextWrangler
Pros:
Free
Customizable colour themes
Find/replace regular expressions
Cons:
Weird window management
Hard to customize colour themes
Nuggit
Cheap
BBEdit
Pros:
Customizable colour themes
Find/replace regular expressions
Cons:
Not too cheap