Summary: Latest HD2500/4000 driver (184.108.40.20632, or x.x.x.2932 depending on exactly what graphics driver package is downloaded) still has the problem of occasionally failing to restore video when resuming from S3 sleep mode. The release notes for the driver say this issue is fixed, but it's not.
i5-3570K CPU, not overclocked
Intel DH77KC motherboard
Dual displays, primary on displayport, secondary on DVI
No PCIe graphics card, just using HD4000
About 1 in 5 times the PC exits S3 sleep, the primary display (connected via displayport) fails to turn back on. The seccondary display, on DVI, always seems to turn back on.
A poster from Intel on that other thread asked if the newest (x.x.x.2932) driver fixes the issue, and I can report that is DOES NOT. Further suggestions, or a driver that really does fix the problem, would be welcome...