I often recommend stocking the following five resistor values:
220
470
1K
4.7K
10K
The 220s are used for series pin protection; the 470s for LEDs when you're only going to light a few; the 1Ks for LEDs when you have a whole bunch and need to limit the overall current; the 4.7Ks are used for I2C and 1-Wire pull-ups, and the 10Ks for standard button/switch pull-ups/pull-downs. I actually have a five-compartment plastic case that I keep these in.