that color project is super interesting, thanks!
my take on color in logos is that the colors should mean something (i.e., help tell you apart), and be simple. use color as a design element, instead of just making the logo full color (like the photos mentioned above!). it isn't a logo unless it is simple, i think.
honestly, in most of my projects i don't make a logo right away, i just pick a color. for example, my vagina website (http://myvag.net) is pretty much just blue with a font, and the art collective i work with just identifies as orange (http://alohamedia.net). i find it easier to pick a color that explains a project than draw a shape.
i really like your rocking horse logo. the monochrome greens to me evoke stuff like victorian toys and beatrix potter and classy childhood items. it is different than if it was pink and white (sissy, pretty, fluffy), or bright purple and yellow ("funky"). it would also be easy to print it as a black and white outline if necessary.