There are a few things I notice don’t work properly or just look bad. Since I easily found alternatives I have not looked into the cause of the issue.
Plugins Used:
I was using the pluginsUsedPlugin from Andrew Chen but this no longer renders anything. I did like the simple and clean list output it gave. This plugin still works great on my main blog (Harrison Blackwood) using WordPress 2.6.2 and K2 RC r718.
I switched to WP-PluginsUsed from Lester ‘GaMerZ’ Chan. This plugin adds more advance display choices. I use other plugins from Lester ‘GaMerZ’ Chan and they all work great.
Last.fm:
I stopped using the code snippet from last.fm in a sidebar module mainly because it looks dull and overly simplistic. I still like the last.fm generated widget but I want a more graphically pleasing one. Since I am only using one sidebar with a limited number of modules a graphic version looks better and doesn’t get lost if in an overly busy set-up.
I switched to Last.Fm Records plugin from Jeroen Smeets. This works great and is simple to set-up and use. The current version 1.4 requires PHP 5 which causes a problem for my other site so I use version 1.3.1 there. I’m looking into changing hosts for my other site.
Flock:
Flock badges are not currently working/linking. This could be more related to their website and the recent release of Flock 2.0 from beta. I changed the badge to just a text link for now. I still want to show support for this great alternative social cross-platform browser.
Everything else works ok with my current versions of WordPress and K2.
The new interface may take a little time to get used to for some. I like the uncluttered look.
bleeding-edge to hemorrhage -> NOW: almost-beta

Well, I finally updated my version of WordPress to version 2.7-hemorrhage manually. Everything went smooth. After I finished I checked for an update to the nightly build of WordPress 2.7 that I had from a coupe of days ago - now reads 2.7-almost-beta. Still using K2 theme revision 721 no problems.
Testing iPod Touch blogging using WordPress app.
Typing is a bit slow. Short posts would work best. Just like using Twitter.
Upgraded to Wordpress 2.6.2 today and using the K2 theme revision r718.
Everything works now but the upgrade process using InstantUpgrade 1.0 beta2 did not go as quickly or smoothly as in the past. All that happened was I had to reload the confirmation page 3 times. Eventually, it failed with some lines of code that I did not copy. I just went back to my blog start page and re-logged in and everything works great.
I know this plugin is still a beta. I guess I could try a different upgrade plugin but this one works well enough for the test site.
I am currently using K2 RC7 r718 theme with WordPress 2.6 with no noticeable problems or issues. Check the plugins used About sub-Page for what I am using on this site.
The current nightly of K2 revision 703 and WordPress 2.6 are working correctly together. I have not seen any issues.
A key component is the new plugin to enable the K2 SBM to work with Wordpress. The added k2-disable-widgets.php plugin brings back K2 SBM functionality that were are all used to.
Thanks to all the K2 developers!
Everything appears to be working once again. Using the new release version of WordPress 2.6 and nightly version K2 RC6 r695 the sidebar manager works almost correctly.
After further experimenting, the K2 SBM does not delete added modules but you can drag them to “disabled” to remove them from showing. This is only a minor annoyance. When I try to delete unwanted module my site reverts to widget use. I have to re-select save from K2 options to re-activate SBM.
Although WordPress 2.6 beta1 did actually work, it did not play well with the K2 theme (using nightly RC6 r692). WordPress 2.5.1 worked great with K2 r692. I have grown accustom to the K2 sidebar manager over widgets since early days of K2.
A new change I have noticed, the ability to edit individual sidebar modules from actual page display with edit link versus going to the admin dashboard.
I have reverted back to WordPress 2.5.1 today. I had too many issues with 2.6 beta1 and K2. Mainly sidebar manager issues.
It’s a beta, enough said.
I added a plugins used sub-page to the About page but due to the problem previous mentioned I can not get it to display the way I would like. On the About page only.
Plugins Used
I need to add tags and catergories for my posts.
This is now resolved with K2 r703, from 7-18-2008.