The template is whatever suits you best, really. Microsoft Excel, just like Openoffice Calc, is already set to do everything. First line have the name of your columns, you can stick it on top of you screen so that it always shows, same for the first column.
My columns are: name of the game, console, region, another column I labelled group so that I can sort all Shinobi (or Sonic) games together if needed, then three columns cart / manual / box with an x in it if I have it, three columns price / postage / total for how much I paid for it. Plenty of columns if I need to add extra information. I wanted to add the release date so that I could make some nice data analysis about which era I like best or something, but then I gave up finding it for each one of my 300+ games.
I have on a second tab my want list, more succinct with only game, console, region, how much I want it (very much, not so much, not before I have everything else). I can put everything in that list, from games I lust over to games mentioned in passing on NeoGAF which may be mildly interesting. Unlike a software or a website I can add anything I want however I want, without cluttering the view.
I'm using it in parallel with a website so that I can access my lists even when I'm not on my computer, but the website is often dragging behind because entries need to be added every so often to the database. Which reminds me I have another column in my have list, in which I put a P or a M depending if the game is missing from the online database or if I haven't bothered putting it in yet.