This is on Textmate 1.5.9 on Mac OS 10.6 (Snow Leopard). These are just basic tweaks to make the editor slightly more useful and to avoid mixing tabs and spaces in code.
Tabs and Spaces
Please do this! Mixed tabs and spaces in code is irritating and screws up diffs and code display.
In the bottom of the document window click Tab Size: and select 4.
In the bottom of the document window click Tab Size: and select Soft Tabs (Spaces).
It should now read Soft Tabs: 4.
Text Display Preferences
From the Textmate menu select Preferences.
Click the General tab.
Select Highlight current line.
Select Show right margin indicator.
Click the Fonts & Colors tab.
I like the Slush & Poppies theme, but that’s just a personal preference.
If you're on Mac OS 10.6 (Snow Leopard) click Select… next to Font and choose Menlo, Regular, 12 pt. which is a much nicer fixed width font.
View Preferences
Line numbers make code navigation easier:
From the View menu select Gutter -> Line Numbers.
I also like to show invisibles:
From the View menu select Show Invisibles.
