Planning on building a community, be it in the form of a forum or web chat or blog, and planning on being big? Do you invest in shared hosting until you can't hold it any longer, or do you invest in big hardware which should be able to handle the load as it increases over time.
Are you satisfied with IDE hard drives on single CPU with 512mb ram systems, 10mbit network that works now, but might get slower in the future?
Or do you not mind investing money into SCSI setups with dual CPU and at least 2gb ram on a 100mbit or bigger network.
(not taking into consideration how the software might be setup).