Paint.net or Gimp? Which one should I choose?

This is worth getting.
Just for the things you can do on it
Photoscape: http://www.photoscape.org/ps/main/index.php

also

paint.net: http://www.getpaint.net/index.html

and

Lightbox 2.0 Free version: http://www.sagelighteditor.com/downloadfree2.html

Basic editors like Lightbox allow you to quickly make small adjustments to the overall lighting, colors, and tones of your images (along with other tools: cropping, sharpening, red eye correction). But editors like Paint.net offer more advanced tools (layers, captions, shapes, selective adjustments, artistic effects, etc.).

Or

then there's Gimp: http://www.gimp.org/....gimp.org/
it's like paint.net but slightly more complicated.
(a bit like photoshop)

(ALL Free)