Well having an HTML gallery would indeed provide you with a very minimalistic approach both on the technology side and the user end's side.
Basically, the thing you should be considering is who is your target audience, indeed Flash Galleries do provide a significant amount of interactivity which will intrigue and amuse your users but if it comes to the expense of performance and speed of displaying your gallery, I would suggest that you stick with an HTML based gallery.
If you do decide with making a Flash Gallery, Adobe has a number of software that can automate that for you.
Photoshop CS4 has plugins that would allow you to export to Flash Galleries
Photoshop Lightroom 2 has this build-in
Flash CS4 has a infinite number of templates and tutorials available on the web on how to create you Flash Galleries.
Agree with c0j!!
Personally I feel that its really about choosing the right tool for the right job, and that depends on the requirements you have (whether from your "wish-list", or the requirements from your audiences).
I'll recommend you to choose Flash if you require:
- high level of user interaction
- some Rich Internet Application features, such as provide zoom in/out, change image orders, coverflow effects...etc to your gallery
- you have allocated budget and time, and
- this is not intended to be a viewed by mobile phones (its possible, though, but a bit difficult)
- No-frills, just a simple image gallery
- minimal level of user interaction
- no RIA features
- you need to get it done within 4-8 hours
- should be compatible to be viewed by mobile phones
And of course, if your requirements are actually somewhere between these 2, you can always do a hybrid, having some RIA stuff done by Flash, and other simple stuff done by HTML.
Just sharing some thoughts...hope they help