IF I remember correctly:
Debian 5 uses 2.6.26 (also 2.6.31 was made available optionally)
Debian 6 uses 2.6.32
Next Debian will apparently use 2.6.38 (the version currently in testing)
OpenWRT-git recently switched to 2.6.37 from 2.6.32
Nobody knows what Google does, but at least the normal distros will switch to 2.6.37+ soon.