Downbeat is also sometimes referred to as "down-tempo" although i prefer downbeat. It is frequently confused with trip hop, and sometimes artists who do one also tend to do the other.
Another great example of a good downbeat artist is DJ Krush, and Kruder and Dorfmeister. Both have big smoothe beats, with little to no atmospherics. Their sounds are more traditional big beats, with some samples. Mostly groovy beats.
Good downbeat artists to listen to...
DJ Krush
Kruder and Dorfmeister
Orb
Massive Attack
Portishead
Moloko
Baby Mammoth
Fila Brazilla
Thievery Corporation
The Herbalizer