My preferred oscillator basically is...
but without the attenuator to avoid the ESD diodes... since my custom stuff has no ESD diodes on the internal nodes.
Also the inverters are single stage instead of the 3-somes built into the 74HC04's
U1A, in my designs, is often an NMOS device plus a current source pull-up, to minimize power consumption.
In a recent RFID tag design, a 2MHz clock runs on 1uA ;-) (1.2V supply.)
...Jim Thompson