As far as I can see, so far camera models is mostly used with the camera name, like
[canon-g11], which makes sense. I see some exceptions where both exist, like
[t2i], which should probably be retagged after we decide what the format should be.
The EOS term is however a bit different, as it applies to all Canon SLRs, both to digital and film cameras, so it's mostly equivalent to the
[slr] combination. As it's so wide, it's not very useful, especially as most qustions that relate to cameras in the EOS series won't be tagged with it. Perhaps the
[canon-eos] tag shouldn't exist at all.