I've been using MacJournal for some time now, and have been quite happy using it as my outboard brain (for accounts, registrations, code snippets...) but it started barfing on me over the last couple of weeks - new entries not saved, etc... I know... MacJournal is open source (well, the source is available, anyway), so why don't I just fix it myself? I've got enough of my own code to manage without taking on an unrelated project. That, and I'm getting lazy in my approaching middle age.
As a result, I've been looking for another solution to hold any kind of data that may not belong in a weblog (which acts as my online brain). Enter DEVONthink Personal Edition. I'm trying it out, and it seems quite cool. The only real improvement I can think of would be concept mapping to show the relations between items in the database.
It does have a cool "similar items" thingy that seems to do a decent job of finding items somewhat related to the currently selected item. Could be cool. I'll update if anything exciting happens with DEVONthink.
UPDATE: Got my registration for DEVONthink today. Rock on. Also talked to their feedback/support folks. Apparently they are aware that concept mapping of items in the database would be cool, but it's lower on the list. If that's important, send them some feedback...