I have recently worked on the client site (SQL Server 2000) to help on optimization. They have a very huge table (about 250 million rows) and perfom rebuild index every day at night. That jobs has beeen completed in two hours or so till this monday. The job was in 'executin status' for more than 10 hours and imagine what happened to the LOG file. My first thing was it would be really helpfull to have any system table that shows a percentage or whatever about the rebuild index process (something similar to what we have in SQL Server 2005 for some commands (BACKUP DATABASE) to see percent's complete )as I did not intend to KILL the process.Finally we got on and the process was completed. I suggested to the client rebuilding only heavy fragmented indexes especially if you have such huge table. Also , it is unnecessary to rebuild that table every day (it depends on your business requirements) ,so in their case , it is enough once a week.
In SQL Server 2005 for below operations you are able to see completion time or percent of completion.
SELECT TOP 2 start_time,
ORDER by start_time desc