Great fun this obsession !
Only suggestions... everyone has different interests.
P60's are fun-tastic to play around with, learn the ins and outs of voltage, cells, drivers.
Get a Surefire (you need it to set the basesline) and then go mad in the Lighthound shop, Solarforce, Fivemega, Leef and other extentions and bodies, lots of dropin's , 18650 cells, RCR123, heck even 17500's, P7 turbo head from LF is good.
Make all sorts of lego combinations till you build yourself the perfect light for a task.
And then scrap it and do something else. Or just buy more parts to build the next one!
You might also want to delve into the small twisty keychain lights.
iTP or 4Sevens A/Mini series for a start. (oops, see you have the mini, get a AA and AAA type, or 10)
What about something like a Surefire LX2, thats on my agenda next. I have just ordered my Quark fix and awaiting patiently for it to arrive.
You DESERVE a Thrunite Catapult
Whatever, where does your interest take you?
Thats just LED, what about incandescents !?