Choose Options/Colors to select colors used for the Log, Packet and other windows.
Choose Options/Sounds to select the sound used for beeps in the Log and Packet windows.
The available sounds are defined using the "Sounds" item from the Windows control panel. Normally the four available sounds (Critical Stop, Question, Asterisk, and Exclamation) are set to the same value (chord.wav) so if you want the Packet and Log window beeps to be different you will have to experiment with these settings to find something you like.
Choose Options/Log Fields, Fonts, Default File... to select the font used for the Log window. You can also set the font used for reports generated by "Display/Short..." and "Awards/..." etc..
Choose Options/Packet Options and Port Select and pick the Options tab to select the font used for the Packet window. It's best to use a fixed-width (non-proportional) font for the Packet window so that data will line up correctly by column. Some commonly available fixed-width fonts are Courier, Courier New, Andale MT, FixedSys and Terminal.