Get good tools There are far worse things to spend money on! Some good things to have, and I realize most of them have been suggested already:

small chain tool
crank extractor
cassette lockring tool
chain whip
cone wrenches
axle vise
headset wrenches, if you have a threaded headset
cartridge bottom bracket tool
pedal wrench
folding hex-key set
spoke wrenches
high-quality cable cutter

and perhaps a repair stand, a repair manual, and maybe a wheel-truing stand if you want to spoil yourself Virtue is its own reward, and nice tools likewise. Park Tool's stuff is generally worth paying extra over the generic-ish stuff IMHO.