In some computers, when I put them to stand-by, they do not shut down their fan-based coolers. Even though they go stand-by (and can be waken up with the mouse), they just don't shut up.
I have no idea if the CPU is still consuming power, but it's cooler is, and also the case fan.
I'm sure the PC is in stand-by because a decorative light in its front blinks, which makes me believe the motherboard understands what stand-by means. Also, the CPU's fan in wired into the mobo, not directly to the power source. The network card shuts off (the LED goes off) and the hard disk spins down, but the fans are still on.
It's an old ASUS A7V8X-X with AMD Athlon XP 2000+, but it also happens to another, old, ASUS A7N266-VM with AMD Athlon XP 2200 (update: In which case it may be expected, as only the case fans, connected directly to the power supply, keep running). And it also happens to somebody else's PC with unknown specs, so it's not that my PCs hate me. I guess. Dunno.