The EPO is conducting a survey on a proposed improvement to esp@cenet scheduled for 2008. Specifically, they're asking for feedback on the usefulness of exporting data in CSV or XML formats.
Currently, the only patent office database (that I'm aware of) that supports exporting is the German PTO's DEPATISnet. You can download bib data in an Excel spreadsheet from up to 250 records at a time.
This is a wonderful development. At my university a number of engineering and business students take entrepreneurship courses that require them to use patent data to identify key companies/innovators, develop market profiles and analyze long-term industry trends. Being able to export data from esp@cenet would save them a lot of time. In my opinion, CSV is more useful than XML, especially for users such as students and private inventors who are not familiar with XML, since it can be easily imported into a spreadsheet for analysis.
If you're an esp@cenet user and would like to provide feedback, go to the esp@cenet forum at http://forum.espacenet.com/ and look in the Information Channel. You will need to register in order to submit comments and vote.