44.1 or 48?

A colleague recently asked:  "Can anyone honestly tell the difference between sound that is sampled at 44.1k from sound sampled at 48k?"

No - assuming you're sampling on the same piece of equipment.  (Keep in mind that converters on box A might sound much better than box B no matter what the sample rate.)

Rule of thumb - sample at whatever rate your final project will need. If you sample at 48 for a 44.1k final format, it will typically sound worse than if you sampled at 44.1k to begin with.

Unless you can sample at 96 and fidelity is worth the trouble - for classical music recordings or birds singing for example. You'll have to downsample, but you'll have the original 96k recording for future hi-fi formats.

Different rule for bit resolution:

A noticeable difference is found when increasing the bit resolution. 20bit recordings sound much better than 16 bit recordings, and it is better to sample at the higher bit res even if you are to downsample later.