

Sound effects in comics have to be chosen carefully, or you fall into the category of "that dude who writes comics about dongs." Incidentally, this never happened to Herge, but only because Cracked has not decided to bestow that honor upon him (yet).
Comic book sound effects have to concisely express a particular sound without any ambiguity. "DZOF," as shown above, does not fit into this category. What is the sound here? Short and sharp "DZOF" or more of a booming sound "DZOF!"? In general, avoid consonant combinations favoured by ex-Viking countries.
Unless your comic is meant to be funny, avoid sound effects that actually look like words. "BAF" works well enough for a punching sound, but "WANGO" takes you out of the realm of the dark and eerie and places you squarely in the 50s.
Cracked Talk on | Comic Book Sound Effects
Comic book collections at http://www.rillabooks.com/classifieds http://tinyurl.com/yzerkmu
the POW was quite funny
'Thoom', plus a slightly unfortunate picture (picture is SFW, text is not): http://i924.photobucket.com/.../AnalFisting.jpg