I use a few different really cool plugins on this site. But I have loads of issues with them. With a couple, it's because the developer seems to be busy and doesn't update them much. I'm not competent with php yet (only enough so to use WP template tags) and so I can't really develop for these - I don't really contribute much to the community, I guess.
So, one of the cool plugins I used is actually based on technology a guy I work with created. Jared (my office buddy) told me who created phpflickr a couple months ago (it was Dan Coulter, who's our db admin here at GC). phpflickr is sweet. And the plugin I use is called wp-picturegrid created by Kieran Delaney.
The only thing I wish it had (which Kieran commented about adding back in January) is the ability to pass variables to the plugin by way of my page template. But I can't. So, if I want to display my picturegrid in the sidebar on most of my pages, but in the content section say my Photos page - I am stuck with one count size. I can only use the plugin Settings page in WP admin. So, nine photos in the sidebar (to make it all look even) and nine on my photos page. It's frustrating. It also doesn't work with the lightbox plugin it's supposed to work with. So I don't include the lightbox option.
It's a cool plugin, but still rough around the edges.
More plugin reviews and recommendations to come.