You can trust the guys at Juice to put together great lists of resources. Their recent Essential Excel Skills blog post and the Excel Core Knowledge Wiki are excellent examples showcasing fundamental skills no analyst can do without.

Top Resources for Analysts: Excel, Data Analysis, and Business Intelligence is another list you shouldn’t miss.

If you work with data for a living, the following sites are worth a visit (or a subscription) to learn from some of the best, most passionate practitioners.