I tried various fonts and font sizes with XTerm and recently I settled on Lucidatypewriter 12 with a window geometry of 90 x 24.
Here's how the line looks:
/usr/bin/xterm -font -b&h-lucidatypewriter-medium-r-*-*-12-*-*-*-*-*-iso8859-* -geometry 90x24
Here's a quick run down.
Launches the xterm application and gives the path.
Tells XTerm watch out, here comes the font I want.
Gives XTerm the font details.
Tells XTerm to use an initial size of 90 wide by 24 chars high.
You can try other sizes if ya like such as 100x20 or so. But 90x24 works well for me.