MOTM

Thanks for the dirt on the LEDs.

Next question:  I would like to collect a few Op-Amps to keep around
for DIY fiddling.  Any recommendations for the top 5 candidates to
keep in a well-stocked MOTM experimenters work bench?  A general
purpose Op-Amp to drive LEDs.  An audio preamp.  That kind of thing. 
The TL072?

Thanks,  Greg