growing disk usage problem: alternative solution?

Hello List

I have been a user since 7.x version.  My current server version is 8.1.2.

As many of you know the disk usage keeps growing for postgresql unless one regularly reindex and/or fully vacuum.  The
problemwith either method is that they lock the tables and it is not practical for databases that one wants to keep it
availablefor 24x7x365 basis.  For very large tables, while the tables are being reindexed, there will be many waiting
update/delete/insertprocesses and this is not at all desirable. 

Server response is still great even with growing disk usage.  Any one has other ideas to check the growth of the disk
usage.

Please do not cc the response to me.  I will read it in the list.

Sincerely

Z-m Wu