I like the data import wizard a lot, guys. It's an amazing piece of work.
Here's a small enhancement request that would take a lot of the drudgery out of importing CSV files.
In the Choose Columns section or Import Method section, add an option to automatically replace invalid characters in column names (like replacing spaces with underscores). This would save a lot of tedious hand editing, especially when you get large files with lots of columns.
Thanks! Keep up the great work!