Personally, I use Excel. (Wait, come back, I'm not crazy!) For a bigger / team project, I've gotten a ton of mileage out of Bugzilla, but that tends to be kind of overkill for a one-person project.
But, a well-organized spreadsheet, with columns for things like "status", "description", "code module", "resolved date," etc, gets you pretty close to what you'd need for a small project. Sorting a spreadsheet by column isn't anywhere near a search, but its a whole lot better than "find in text file."
Heck, if you use Google docs rather than excel, you can even publish the thing as an RSS feed and get it anywhere.
And, the major advantage is that the setup time and learning curve are both effectively nil.
Addendum: And of course, the instant your "One-Person Bug Tracker" becomes a "Two-Person Bug Tracker" you must switch to something better. Bugzilla, FogBugz, anything. Trust me, I've been there.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…