I guess this depends on how profesional you want to get. The Amiga is quite outdated for quality vector tools.
If you want very profesional you aught to use Illustrator for vector drawing, and max/maya/lightwave for rendering 3D logo's.
If your on a budget then inkscape and blender will do the job (both free).
If you must go amiga, then use what the guys have mentioned below. Don't use ImageFX, it's a pixel tool, and unsuited to logo work (apart from one off's that you won't need to scale).
Don't forget you can run some older Mac stuff under emulation. I used to do this back when I was studying graphic design, but could not afford a MAc classic. Photoshop, illustrator, free hand and quark can all be ran this way (much older version though).
