I5 2500k idle core temps, are these stable?

yes, thats 2 high. Since your case has adequate ventilation I would guess you had a bad heatsink mounting. When you get a chance, reseat the cpu and check the difference.

Are you using speedstep? Or are you OC''d all day. What is your OC multiplier and at what voltage?

your temp should be a lot closer to ambients unless your not REALLLyy idling.

Not too high at all. My Q6600 and i5 2500K both ran/run 39C @ idle (OCZ Vendetta 2 and Zalman Flex w/2000rpm fan), and both overclocked very well. 3.2GHz and 4.5GHz respectively. Both staying under the 71C limit recommended by Intel.

BTW, the last sentence in your reply should have been the basis for your first question.

"Where do you live? What is the weather like outside and inside?"
A computer in Brazil will not have the same temp as that same computer in Russia.  

Thermal paste application method and heat sink seating, should have been asked second.

I should have specified more clearly by stating "before I overclock". I am running at stock settings right now. I overclocked it using automatic settings Tuesday after I built it. On 4.6ghz I was running around 70+- in prime95.

The CPU dye temp is around 26-28c.

I will say. I had a little trouble getting the heat sink on the first time. I took it back off, cleaned it and reapplied paste. I am thinking that maybe I didn't get it on there good enough. I may take it off this evening and try again just to be safe.

Does anyone know of any good articles for the 2500k and P8Z68-V Pro?

Best answer selected by wireeater.

ok those new numbers you posted look a lot better, but they really mean nothing. We need to know your exact load temperatures. But as colonel nerd rage stated, anything below 70ish is probably fine. Glad the reseating worked out for you. Thats usually the issue if your case ventilation is pro. I have never pushed one past 65c on air and maxing out at 50C on liquid.

What kind of articles are you looking for? Nothing tricky to basic overclocking really. It is not really mobo specific, although your asus probably has some neat automatic features and clickable bios. Look up a few youtube videos on how to overclock 2500k or any cpu for that matter. ENJOY!