Personally I hate the default font and color settings of the mIRC client.  So I change them and I suggest you do the same to give the program a more personal feel.  Changing fonts is very easy, if a bit redundant.  Simply make sure your channel folder is the active window in your mIRC client.  Then choose the "Tools" pulldown menu on the mIRC toolbar and the click on "font" at the bottom.  The following dialogue box will appear.  Simply select your desired font, font style, and size.  Make sure you check the "Set as default channel font" check box or it will only apply to the current change window and will reset to default fonts after it is closed and reopened.

Now that your channel font is done you have to do the same thing for your "status" window and "query" window. Make sure the respective window is selected and repeat the process.  Make sure to set as default.

To change the colors, select the "Colours" option from the "Tools" pull down window.   The "mIRC Colours" window will appear.  Just select the color for the appropriate item in the main field in the window and select the color in the palate.