I must admit that my initial reaction to your post was the same as the 2nd poster. something long the lines of “How could we possibly recommend a scope without knowing what your needs are.”
BUT, then i re-read your question -
mprev:
I really like the Sparkfun approach to products and would love to hear their opinion on the scopes out there.
and I now see that you weren’t asking that. You were asking to understand oscilloscopes more, and hoping that SparkFun could write-up a walk-through/tutorial. That seems like a fair request.
I did find a few site, that may be valuable for you to look at, while you wait (and hope) that SparkFun might fill this need. (These aren’t exactly what you’re looking for, but maybe they will help a little.)
A decent tutorial is here:
https://www.cs.tcd.ie/courses/baict/bac/jf/labs/scope/
A 3 part you-tube video on using o-scopes are here:
http://www.youtube.com/watch?v=qIfo_-d82Co
http://www.youtube.com/watch?v=hUIgAu3QQWQ
http://www.youtube.com/watch?v=g_KuGEh0PyA
Also, depending on what types of circuits/projects you want to use an oscilloscope for, your eventual device can range anywhere from the PC-Based “Logic” device that sparkfun sells (for debugging/troubleshooting embedded electronics stuff), to a used (older) scope from eBay for troubleshooting analog signals, to a full blown MSO/DSO scope from Tek or other company for doing both.
In general if you want a standalone, modern, color LCD based O-Scope with decent bandwidth - you’re probably looking at $600+ (with most starting at $1000).
If you also want to be able to do logic capture/analysis on it, add another $1000,
If you also want to be able to auto-decode protocols (ex: capture I2C traffic and show “address=D0”, “data=C5”, instead of having to count the 1 and 0’s) add another $1000. (This gets really expensive on standalone scopes, and is the area where PC-based devices really shine on better features and much lower cost.)
I personally have the following scopes, feel free to ask questions about them (newest purchases on top):
Tektronix MSO 2012 (standalone LCD o-scope & logic analyzer w/ multiple protocol analysis modules)
Saelae Logic (PC based - protocol analyzer) - available from sparkfun
LogicPort (PC based - protocol analyzer)
Cleverscope (PC based - o-scope & protocol analyzer)