grelmar - 12:15 am on Sep 28, 2011 (gmt 0)
Always patch. Always. And do it as soon as you see it come out.
Vulnerability exploits can appear within hours of a patch, and sometimes before, as the patches are often reactive to a known vulnerability, and for a pro hackers, they actually build bots that search google for files and headers unique to specific versions of WP installations, thereby making the hijack/hack fully automated. They can take thousands of sites per hour.
As for your plugins, I did some testing on 3.2.1:
All in One SEO Pack -> some garbled output, but basically works.
Custom Field Template -> Seems fine.
NextGEN Gallery -> Not a problem whatever, so long as the plugin itself is up to date. Use this on a number of sites.
If I get a chance, I'll test the others later on tonight.
If updates worry you, keep a separate installation going (you can have a second domain with a vanilla WP installation running for less than $100/year, well worth it for testing purposes), with a mirror list of plugins. Test every update there and see where you run into problems.