Well I'd personally say anything under 90*C on the hottest core under Prime95 (27.7 or later) or IntelBurnTest/Linx (with AVX) is ok.
If you see that kind of temps under those kinds of loads you'll rarely see those temps under normal loads, I'd like to say never though. P95 and Linpack are just plain brutal.
P.S. My 3770K could be stable under 5.0Ghz. Haven't actually tried any higher multiplier to see if it can boot those.
I've done some benching at 5Ghz but stable, nah, not with my cooling. I'd need to get some better cooling.. True Spirit and a lonely GT AP15 isn't going to cut it.
I use my 3770K for encoding and such and so my storage is the bottleneck even at just 4.3Ghz. I currently have it at 4.5Ghz just because it's a nicer number than 4.3...