I'm trying to improove my cake toppers (especially figurines). Now I am using gumpaste (home made fondant mixed with CMC), but often I am not 100% satisfied with my work. Sometimes there are cracks on figurines, although I'm very careful with kneading fondant. I'm thinking about trying to make figurines of marzipan or modelling chocolate maybe... Can anyone give me some advice which one is better and why? Thanks.

Marzipan , I found is incredibly hard to work with unless you have cold hands all the time. It also tends to settle into squatty looking figures. I'm a believer in the fondant/gumpaste combo.

modeling chocolate for figurines - dries instantly, easy to sculpt with and blend seams in. I've used gumpaste and even MMF mixed with Tylose but you have to build all the pieces separately, let them dry for a day or 2 then assemble. With mod choc you can build everything up at once easily and quickly.

I don't like gumpaste for figurines. I use fondant with gum tragacanth powder mixed in (about 1tsp per 500g fondant) and that works well, although yes I do have to build in 'stages' (ie I'll build up to the waist, let dry a day, add the torso, let dry a day, then add the head and let the whole thing dry well).

I've not tried modelling chocolate though, but keep hearing good things about it. Do you make your own AngelFood? and if so is there a specific recipe you recommend?

You'll love working with it Coral3. I have the recipe I use (with Candy Melts) on my blog:
http://sugarsweetcakesandtreats.blogspot.com/2011/03/how-to-make-modeling-chocolate.html

I personally prefer modeling chocolate as well because the seams are easier to "clean up".