Using True Type Fonts
To improve the font set available to Debian (and Linux in general) download and install True Type Web Core Fonts. These were made available by Microsoft in a moment of madness, then later pulled (donaters remorse).
# aptitude install msttcorefonts
Debian will download and install the fonts ready for use.
These are my KDE font settings:
General: Tahoma 8
Fixed width: Courier New 9
Toolbar: Tahoma 8
Menu: Tahoma 8
Window Title: Trebuchet 10
Taskbar: Tahoma 8
Desktop: Tahoma 8
Use anti-aliasing: Enabled
Force fonts DPI: 96 DPI
Exclude range: 0.0pt to 12.0pt
Hinting style: Full (could be reduced to Medium)
It makes such a difference. I did a previous post on Poor Fonts in GTK apps running in KDE.
There's a good read on Linux fonts: Optimal Use of Fonts on Linux. It has some spelling errors and typos, just ignore them.
That's about it.