I'm looking for a good way to learn more ArcGIS techniques than I came across in my undergraduate Geography degree to really use the power of the software.
Browsing around and asking questions on this site has helped quite a bit e.g. I did not realised that you could link dataframes together, or even that you could have multiple data frames ([see How to provide automatic overview map in ArcGIS Desktop?).
Similarly, I suspect there are lots of ArcGIS features that could really make my life easier, but that I just don't know about e.g. geodatabases.
What I'm really looking for are tutorial recommendations, in any medium (books, videos, websites, whatever). Obviously free or cheap are better, but I do have a budget for books as part of my PhD. As I probably hinted at above, I'm more interested in general usage of ArcGIS rather than specific tools (like DEM processing or route-finding), and something that is relatively structured would be good, so that I can work through it in a sensible order.
I know this is a bit of a tall order, but any ideas?