Thanks David, that's great to hear! Unfortunately I am currently moving from Sydney, AU, back to The Netherlands, so I am not able to help you - maybe somebody else can...
About tooltips: I didn't know that you can turn on hex display (how can I turn that one?), which is clearly the most important one - sometimes, binary is useful too, e.g. when checking which flags (bits) are set.
Second, it would be good that when pointing to a field, the value of the field would be shown in the tooltip, e.g. e.Message would give the message text, instead of finding the text by browsing through the whole object's tree. In addition, when browsing through an object, maybe you can maintain that state as well, so that the next time you point to e, it will open up as the last time, and you can immediately see the field you've selected previously.
Finally, about Image tooltips: for Visual Studio, here's an interesting example on The Code Project:
http://www.codeproject.com/csharp/ImageVisualizer.asp
Cheers,
Erik