I've been using a software program from Acoustic Sound that is exportable called Keeptrak. A trial download is available at: http://store.acousticsounds.com/browse_detail.cfm?Title_ID=9417
I have a low-tech approach and use Excel.
At the same time I put a title into Excel, I add it to a HTML file which I upload to my Geocities web site. I can write HTML, so I'd rather do it by hand than have Excel export a table in HTML format.
The spreadsheet is useful when I need to resort to check something (like how many multichannel hybrid SACDs I have). Of course, it can go on my PDA.
It's very time consuming to get all the titles into whatever system you use, but once they are in there, maintenance is easy.