Well it's party true... You see by the HijackThis log what infection does the OP have; therefore you know what tool to use.
ComboFix covers more infections but shouldn't be used so easy; only if you really see it's needed. It also isn't suggested for use without some expert's knowledge and refference.
SmitfraudFix cures Smitfraud infections, also hard to use if you know nothing about it, and can do some damage ( remove desktop background

).
SDFix and VundoFix are too specialised for only one type of infection, SDFix cures Trojans while Vundo fixes Vundo infections.
More about all of these, if you are interested in learning, start some university. There are good ones on google, but I can tell you if you show some interest in it.
And I have to defend HijackThis, you see, most of the infection will not be cured totally if you don't eventually fix them with HijackThis; and some can only be fixed using HijackThis ( like browser hijacks ).
All in all, this is enough information for a starter, lol.