This is my personal user experience so far. From a noob stand point mind you...
At first when i overclocked, I kept it running at what most of you are running right now. 800mhz-1ghz max with 250mhz min. Mostly cause i wanted to see how the phone was gonna react to it, and to see how battery life was gonna be at 1ghz.
I was also running the sleep/standby and charging profiles. I had my sleep/standby profile set to 600mhz max 250mhz min, and my charging profile set to 800mhz max 250mhz min.
Well after the first day of using that setup, i noticed the phone still seemed to lag every now and again. Twas rare...but it was still there. So i said screw it, and i decided the ramp up the min to the same as the max. So i was running 1ghz max 1ghz min.
I was a little scared at first, but its actually running fine. Great in fact...
My current setting are:
1ghz max/1ghz min
Charging-1ghz max/800mhz min
Sleep/standby-600mhz max/250 min
I haven't noticed any drop in battery life or excess heat like some of you are saying while in sleep mode. In fact, i get pretty much the SAME EXACT battery life as i did before i overclocked. The difference is minor, and i still will use the phone the same amount as i normally do in a day.
So i mean...thats just my experience so far. Im no tech nerd when it comes to overclocking.