Alan,
I'm reading your question differently than John and Peter. I assume you have no trouble getting GPS data "into" your images. It's seeing this information on a map and offline that is the issue.
Like you I've got many images tagged with locations and want to see them on a map. I have a Garmin 60csx and use ImageIngester to get the data into my images, from where I can see it in xMedia 2. I've been playing with an XSL script that takes xMedia 2 data and converts this into a GPX file. This can be opened in Google Earth, although you have to open it from within the application rather than use "Open With..." I'm a PC man but this solution is cross platform, just bear with me. If Google Earth was my end destination I would have created a KML file, which is the preferred format for this tool. However I can open GPX files within MapSource, which is the application that came with my Garmin device. This shows each image as a Waypoint on a map. The big advantage of this is that you don't need to be online to view this, which I believe is your primary requirement. The only question is that I'm not sure that MapSource is available for a Mac. There is a product called MapInstall for the Mac only but I don't know what this is capable of. Googling suggests it supports GPX files but I can't test this in any way. The packaging for my European map has Mac installation instructions so it doesn't appear to be impossible. Someone must have a Garmin and a Mac?
It's not a perfect solution though. MapSource allows you to add an image to a waypoint. However the current (and latest) version cannot save this information into a GPX file - it can into other formats but these are not open formats. There are a number of symbols you can use to indicate a Waypoint on the map and I've currently got this to show a number from 0 to 9 which ties in with my label values. It might be better for this to show a Rating instead - can't make up my mind, as I'm still playing and learning. You could also use a custom field to define the symbol as there are over 100 built in images for various uses from Outdoor (including a camera), Hunting, Transportation, Business, Civil, Marine, Aviation and various numbers, letter and faces for contacts - an alien? Maybe in America! However I think these may vary according to the device you have. You can also assign a Waypoint to one or more of 16 different categories. I can't find a way to rename these categories yet so you're stuck with Category 1, Category 2 etc, so while useful they could be so much more.
The only challenges so far have been getting around the terrible way that xMedia stores its data. I have to convert latitude and longitude from text values to numeric and also it doesn't store dates in a good format when exported to XML. The former is forgivable, the latter not as there is an international standard for this that the iView team should have complied with - not too late to change!
As the solution is XSL based it will work on both PC and MAC. Let me know if you think this is the sort of thing you're interested in. If so then I'll tidy the script up a bit and post with instructions - will take a week or so to do, as I'm very busy with my real job!
Obviously you would need MapSource to run it. You would also need to get a more detailed map for where you live. I've got the City Navigator European map and it cost £80 not long ago. Obviously there's a US equivalent. These go down to street level and are very detailed. If you needed to keep this up to date there are subscriptions available. Whatever you do don't get the SD version as this is for plugging straight into your GPS device. Get the DVD of data, which you then upload to your device.
Here is a screen shot for a test catalogue I'm playing with. The map detail is low as this is the free world map that comes with MapSource. I should have done this with more local images to show the detail available, however I have a nice test catalogue with every permutation of annotation, and it has no images from closer to home. The 'name' of each waypoint is the filename. The symbol is straight from the label. The 'comment' is from the Headline field. The name and comment can be swapped around or you could use the description field. Too many images in the same location does clutter it up a bit, particularly if in the exact same location, as these examples are.

Anyway just throwing this out there...
Ian