solder, solder wick, some of those switching 7805s from murata, some mosfets (mtp3055, irfp150n), some jfets, some LM324s, some pushbutton encoders (EVE-UPCAH516B), some voltage references(LM4040D41, MAX6126A), some DACs (MCP4921)
these are some things i'd like to keep handy. It really depends on what all you want to make though. It would be best to think about what you would like to make and what it will take to make it, then order extras.