I needed a Tabbing plugin to work with HikaShop product descriptions. I had previously used Tabber with Virtuemart, but needed something to work with Joomla 3.0. At the time of writing this review, YTab was the best tab plugin for J3.0. It works simply and presents nicely and has caused no conflicts.
I had a problem with JComments after upgrading my site to Joomla 2.5.5 (it wasn't a Joomla problem). I got top support on the JoomlaTune forum - fast, efficient, brilliant! And free! I don't know how these guys do it. Well done, JComments team :)