I love the Query Browser and use it constantly throughout the day. Following my leopard clean install I had tons of problems with crashing- it would often crash just on launching the Universal version. By downgrading to a previous PPC version I could use it with about 1 daily crash. Then I discovered that when I didn't have Default Folder X running, the current Universal version ran great. After talking to the Default Folder X guys it turns out that it's a bug in the MySQL Query Browser's handling of AppleScript. Other apps that hook into AppleScript may also cause the crashes. I've been crash free since adding Query Browser to the Default Folder X exception list!