In both my current job and my past jobs, I've worked with CSV files in Microsoft Excel as a matter of necessity. Excel is just too useful not to use (OpenOffice has its own quirks, but that's for another post.) The only problem with Excel is that it formats fields automatically when you open a CSV file by double clicking on it or by going through the File -> Open option (or Ribbon -> Open in Office 2007 and later). Sometimes this is nice, but most times it's a pain in the ass, especially when you want to be able to save that CSV data right back out to CSV again. What happens is Excel converts the values to particular data types after introspecting the data in the cells. This is annoying and stupid, especially when you have financial, scientific and engineering data that's in a format that doesn't fit will into Microsoft's algorithm for dealing with numbers, dates, times, and currencies.
There is a way around this giant annoyance. Instead of taking the easy way of opening the file, you can open Excel directly, with a fresh spreadsheet. Then, on the ribbon, go to the Data tab, and click on the 'From Text' button. This will let you open a delimited text file, and treat it as a data source, and Excel will give you options for opening the file and how you want to deal with its contents. This is much better for dealing with the data, especially when dealing with tab-delimited files.