A bit off topic, and I know I'm sounding like a condescending jerk here but I mean it: but why do people love bugs so much that they want to purchase an entire database program to track them? I mean, if you have more than 10 bugs that are highly important to keep track of, it seems to me that you have much larger problem than whether to purchase JIRA or FogBugz. I mean, either a bug is important to you so prioritize…
I think it's a mistake to think that Jira and FogBugz are only used for tracking 'bugs'. They are obviously used for that but everyone I know uses them to track everything related to their software. Track features/support questions/infrastructure changes etc.
To give you an example, I am part of 50+ developer team implementing straight through processing for a large hedge fund. This involves developing variety of systems which are highly dependent on each other. Jira tells me that I have 120 items which I need to implement by this year end. Mind you, this is just one system. There are at least 10 more systems like that. I can confidently say that there at least 1000 items in our overall list which we need to work on. You absolutely need a tool like FogBugz or Jira to track them properly.