I’ve had this thing in my drawer for 2 years; just got to use it for the first time yesterday.
It’s fantastic – really worth $150.
Saleae Logic Analyzer
Now they have new versions that do analog, too (low-bandwidth, tho).
The nice thing about the Saleae thing is the software – it’s really amazingly simple and effective (you can download a demo from their website without the hardware).
I’ve used other logic analyzers – this is miles ahead. (Also way, way, better than the protocol decode on my new Rigol DS2072A DSO.)
[No, they didn’t pay me anything to write this.]