I had found that I could not copy and paste to and from the computer clipboard into or from a Google Spreadsheet when using a multiple cell selection. More specifically, a Google Spreadsheet's ability to copy and paste within the spreadsheet using the application's Edit menu items works as expected. But to do so between spreadsheets, or from the spreadsheet to an email, would involve the computer's clipboard, and this doesn't work as you'd expect. This is a feature, to ensure that a malicious website cannot use JavaScript to snatch the contents of your computer's clipboard, which could contain confidential information. But I also found a solution:

Google Spreadsheet Copy & Paste to/from Clipboard FAIL

...the workaround is to use your keyboard and to do control-c (to copy from the spreadsheet) or control-v (to paste into the spreadsheet) twice in quick succession. I initially feared that was going to be a deal-breaker for my overall Google Apps transformation, and now it isn't...