Glad to see someone's getting some joy out of 2.x.If you're using Moodle "out of the box" and mostly doing text based stuff, you're OK. Anyone who uses a lot of multimedia is going to have a difficult time moving from 1.9. The file manager alone is enough to give anyone responsible for changing over sleepless nights.
Just my €0.02!
What if you're starting from scratch, like I am? Nothing to drag over from an older version, but will be doing a bit of photo album stuff. Go with 1.9, 2.2, or 2.3?
Personally, Tim, starting from scratch I'd recommend going with the latest stable version available.
However, I'd perhaps qualify that slightly in that there are a few plugins that don't seem to work properly with 2.3 yet (e.g. I believe the OU are working on a couple of theirs for September release, I think) although they do work fine with 2.2 - If you need those specific plugins then stick to 2.2, but otherwise 2.3 (that's always assuming your webhost can provide the correct php etc. requirements!)
Tim - "Photo Album Stuff" sounds more like you need Wordpress with a photoblog.
As to Moodle version. Go with 2.3. But in my opinion core Moodle really needs a few plugins to be really useable. Pretty frustrating and time consuming at times otherwise.
Your project has intrigued me. This summer I was administering a project for summer school learners to do social blogging which included multimedia. I used wordpress, which worked well enough but now I'm looking into Elgg (http://elgg.org) as perhaps a more productive alternative. Elgg is like Facebook but has been designed specifically for social learning.
I'm installing this plugin right now: http://community.elgg.org/plugins/385077/1.8.0%20rc1/tidypics-photo-gallery-plugin
‘That depends a good deal on where you want to get to,’ said the Cat.
‘I don’t much care where —’ said Alice.
‘Then it doesn’t matter which way you go,’ said the Cat.
‘— so long as I get somewhere,’ Alice added as an explanation.
‘Oh, you’re sure to do that,’ said the Cat, ‘if you only walk long enough.’