The resolution depends on the size of your monitor.
yep your right lemme give some info :
15 inch CRT : 1024x768 (sometimes 1280x1024)
15 inch LCD : 1024x768
17 inch CRT : 1280x1024
17 inch LCD : 1280x1024
19 inch CRT : 1600x1200
19 inch LCD : 1600x1200 (not sure to )
20.1 inch widescreen CRT : 1600x1200
20.1 inch widescreen LCD : 1600x1200
21 inch CRT : 2048x1536
21 inch LCD : 2048x1536
i know there are more kinds of monitor but i hope this will help you a bit out
if i missed something orso correct me please