Hi Jack,
Very nice Information but i read in this topic about large pst size and want to share my self experience about facing a problem related to large pst .
Due to large pst i mostly lost my mail of outlook 2007 few days ago and not understand how to split my important pst file then i search it in Google and find out about a tool which is useful for me and split my large pst file in this way i secure my important mail and my outlook also take a good speed after use of tool,you can get more information from this blog
http://exchangerecovery.hubpages.com/hub/Split-PST-File-in-an-Easiest-Way