If you're using KDE, you can go to the power settings in "Personal Settings (Configure Desktop)". That being said, I should warn that the system does not always follow those settings. the command "xset" tends to give better results for me. In a terminal, type "xset -q" to view the current settings. Type "info xset" to get a general description of the parameters.
On my system, I keep the screen-saver off. I simply turn off my monitor if I plan to be away for a time. The only problem that I encounter is that when I turn my monitor back on, the system seems to sense that it is dpms capable and resets the settings on it's own. Even though "xset -q" shows dpms is off, the system will set the timings to 600, 900, and 1200 for standby, suspend, and off. I have to remember to run "xset dpms 0 0 0" to eliminate the timings any time I turn on my monitor after it has been off for a time.