I am looking for a backup to my dSLR that I can take fishing when I don't want a bunch of lenses and so on in the pack. Right now I'm using a Pentax Optio W10 and like its small size and so on, but it lacks any expandability. Polarizers are virtually a requirement for salable fishing photos, so I'm looking for a compact camera that has filter threads. From what I've discovered, the Canon G9 is a good fit except that with the accessory attachment and filter it'd be only slightly less bulky than the SLR. Other options?
What I'm looking for:
---8+ megapixel, ---good glass, ---filter threads ON the barrel, ---minimum 5X optical zoom, sub-$500 price point, ---fits in a fairly small Pelican crush case, though weight in and of itself is not an issue.