Is this what you do? Because if someone sends me a csv file, under your workflow I'd have to open it in a text editor (or a different spreadsheet program) to figure out the data type of each column and run it through a perl script (or awk?). For a few columns, sure. For 200 columns, not ideal. Just to get around using excel's impmort directly. Plus, "taking into account Excel's quirks" is easier said than done.
That said, if you have a script you use that does this, you'd make a lot of friends if you posted a link.
I only do this for automated processes where I know the exact requirements of the CSV and the data is large. I definitely wouldn't do it for ad-hoc type of scenarios.
But for some things it just easier to put out an Excel file. In one scenario I have a set of complext spreadsheets that are updated nightly. I use EPPlus (http://epplus.codeplex.com/) a C# library which updates the appropriate data in the spreadsheet.
In an other scenario, I am taking in transactions (accounts payable/receivable, general ledger,etc.) that are in CSV format, applying some business rules and inserting them into a spreadsheet. This spreadsheet is then used by the accountants to do postbacks to the actual ERP system. I looked at doing this using the ERP's own batch interfaces and couldn't justify the time and expense as Excel was the best way to get the data in.
The above library doesn't require Excel on the machine. With Microsoft moving to an XML format for the file, it's made it much much easier to do these things. This particular library works well as long as you are doing simple data updates. There is no ambiguity in terms of the type of the data as you are able to explicitly state what is stored in the cell.
I would love to know if other library like this exist for Ruby or even Python.
That said, if you have a script you use that does this, you'd make a lot of friends if you posted a link.