I now save TIFF only. I am on a PC. PSE Organizer will show me PSD previews, but the windows explorer will not.
I only download TIFF, if that's an option. I will typically place the preview image in the designer folder, instead of the template folder, only so I don't purchase it again, or to quickly choose something from a specific designer.
sounds like you'd be fine with PSD and PNG for your hybrid needs.
PC does not allow me to tag PSDs or PNG files. TIFF does allow tagging... I tag number of photo spots the designer intended (usually one specific color on their templates... gray, but not always). I can't get too complicated with that, because I could over analyze for hours.... I just do a quick glance and call it... "3 gray spots, 3 photos. Done."
I'm still deciding on what I could do to tag and further classify my templates, but can't get too complicated, because then I won't do it.
simple things maybe, like "lotsapaper" or "bigphoto" maybe. hahah.