Normally, most of the company will go for ISO 9001 first prior to the other standard as ISO 9001 talking about quality which is needed by every company.
FYI, ISO 9000 is a vocabulary document and is not certifiable. It serve for reference purpose to allow person reading ISO 9001 to have a clearer picture on the terms being used.
To know what certification you wish to get, you will first need to identify your needs.
For example, to give assurance on quality, you may go for ISO 9001 which is quality based;
For environmental friendly or green support company, you may wish to go for ISO 14001;
To promote workplace safety, you may wish to go for OHSAS 18001. (NOTE: OHSAS 18001 is not an ISO standard);
ISO 17025 is a standard for calibration and testing lab. Normally lab that providing testing and calibration service for customer will go for this standard.
As harry mentioned, customer driven is another factor. Some customer may require you to certify with certain standards before giving business to you.