Formatting data for product import

In building stores for myself and others I have always wrangled with the data, manipulating it to a clean CVS file to import into cs-cart.

I usually get the data from Product Supplies in an Access DB, I then write a number of queries in Access to format the data for CS-Cart. While it not too hard, it can be very time consuming for the first import, and a pain for each data update from the suppliers.

My question is: What is the easy way to handle data manipulations like this, are there any tools that can make this job easier and less time consuming?

I have used Access, Excel, MySQL, PHP and NaviCat.

Please share any solutions you have used in the past, or tools you have used.