everest for desktop monitoring (numbers are always there in the taskbar along with cpu usage per core or fans if you really wanted).. afterburner/precision/all the riva apps have a good osd for in game
I'm rocking with CoreTemp for CPU and Rivatuner for GPU. Seenas I use Riva for OC'ing my card it makes sense to use that too, and CoreTemp is so silly simple it's perfect.
Coretemp and Afterburner for me, although chucking realtemp in at the same time is cool, the temp change is quite noticable.
just use Catalyst··Overdrive to see you GPU temp. For the CPU, you go with HWMonitor or coretemp, both are good.