I use a blog (Blogger.com in my case, but lots of free alternatives).
I keep a record of each brewday, pasting in the recipe I used at the time. Then if I later tweak the recipe I can go back and see how it's changed rather than having lots of different recipe files with incremental changes.
This way I get useful things like tags, search and hyperlinking, so tasting notes a couple of months later can be linked to the brewday. And it's all backed up for me :)
I keep a separate log of the "bare facts" for each brew in Excel - one row for each brew - gravity, volume etc at each stage. This gives an increasingly accurate set of average grain absorption, boil-off rates, efficiencies, boiler and fermenter looses etc to plug back into my recipe software.