When you want fonts in games, it's definitely a good idea to not
use .ttf fonts. They have to do an incredible amount of extra processing to be converted into images, and it wastes a significant amount of time.
Use this: http://www.angelcode.com/products/bmfont/
It lets you convert a .ttf font into a bitmap font beforehand. They are much, much faster to load. Additionally, you can edit the font image in GIMP or somesuch and have a more intricate look. (Ex: applying grain, edging, glow, blur, etc.)
There is an AngelCodeFont class in Slick2D that loads and uses the fonts generated by the font generator.