Shawn Blanc gives us all a tip on how to make your ~/Library folder reappear in Lion in his review — Use the terminal command:
chflags nohidden /Users/YOUR USERNAME/Library
An alternative is to use the menu command Go -> Go to Folder (or Shift + Command + G) and type in “~/Library”, but this seems rather tedious every time you want to the Library folder, especially if you use it often and with different folders (it pre-populates with the last used folder).
Given that so many other changes have ‘revert’ switches (mail layout, indicator light for open apps, scroll direction, etc), I’m surprised there isn’t one buried in System Preferences. That said, as with most of the bigger changes in Lion, this will end up benefiting a huge majority of users who don’t know – and don’t care to know – about how their system files are organized.