HD Sentinel Pro
is larger and more expensive than you'd probably want, but I still wanted to recommend it; though it does a lot, the footprint is still small and it is portable. Other than that, of course there is SpeedFan
. I've used both, and they both will do what you want (except for the color change on speedfan).
There was also a thread on Tom's hardware a while ago, and there were several recommendations: HDDTemp Hardware Sensors MonitorArgus Monitor
SensorsView (google it- it was blocked from work as malicious services, so I didn't want to post the link)
I didn't any of them (I used speedfan at the time), but I figured I'd pass the recommendation on.