The 74HC138 is a pretty awesome circuit. It can be used as a 6-inputs NAND gate with up to 4 inverted inputs. It even has 8 outputs !
If you prefer the AND function, use a 238 instead. And the '154 has 16 outputs!
For a more universal/arbitrary logic function, add some OR gates to the outputs: this provides XOR and MUX behaviour. And if you can do a MUX you can do a latch!
At this moment, I'm struggling to find decent prices for "littlegate"/"single gate" ICs (in the 74LVC1G and 74LVC2G family). The 74HC138 can be found in decent quantities at decent prices and will probably replace a few gates, for example for decoding logic (I'm looking at the UP/DOWN strobes of the register sets at this moment).