Click her for more information on anti-alias filtering
If you do select a value smaller than 22050 for digital recording it is recommended to use an anti-alias filter.
22050 or 11025 samples/second require slightly less processing power to play on newer Macs and 22254 or 11126 samples/sec are slightly better on older Macs due to the design of the sound hardware but the effect is small.
Either 22050 or 22254 samples/second are good choices for most sound recordings but if the sound is mostly bass you can go lower and if there is a lot of treble 44100 samples/second may be better.
More samples per second provides more high frequencies in the sound but results in larger sound files.