Question about temperature please help!

speedfan never worked well for me, but the fact that temperature are reported normally with CPUid leads me to believe the issue is with speedfan, not your CPU. Ive overclocked a friends 9850, they run hot but not that hot. not while the other cores sit at 40*C. The CPUid one looks spot on though.

1. Speedfan temp 1, 2 and 3 are system component temps, NOT CPU temps. "Core" is the CPU temp. AMD CPU's only have 1 temp sensor for the whole CPU, so you won't see 4 (or 2 or 3) different per-core temps for them.
The CPUid numbered temps are also system components - you'll have to figure out which temp is which component as it varies by MB.
2-4. No problem, so you're OK and don't need to buy anything.

Keep HW Monitor open while loading up the system and going back to idle and seeing if TMPIN0 and TMPIN2 (temp 1 and temp3 in Speedfan) ever change. If the min and max are always the same it's safe to assume that it's an erroneous reading from a sensor that may not even exist.

The 80C may correspond to a non-existent sensor, but could be real. If your MB company has a hardware-monitoring program, try it. One component area that can get very hot is the VRMs (voltage regulator modules) -- I know many Abit MBs had this as a weak point. However, VRMs are rated up to 150C IIRC, so 80C wouldn't be too worrisome in that case.