The battle of the 'omes is on, and the winner is decided by Google and PubMed, the biomedical publication database:
|'Ome sweet 'ome|
The victory of the genome is of course a foregone conclusion. Besides that, it's surprising that the reactome gets so many Google hits, although a PubMed search returns less than a hundred publications containing the term.
I might compile the same figure in a year or so to see if the ranking has changed. In the meantime, have a look here for a critique of 'omics that goes a bit deeper.