to rip mp3s using nero you need a plug-in, i have it and i share it over the gnutella network so do a search for :

nero mp3encoder plugin

as i am sure others will probably being sharing too.

i rip all my audi cd's as i then put them onto just a few mp3 cds.
plus i manage to scratch cds in about a day so i always got backup copies...

i use burn data.. simply because i never realised the was the mp3 option! i think that must have been added in on the update or something...
as far as i am aware both should work, just try it. cd's cost pennys nowadays so its just trial and error my friend.

wav. cant help you, never done it. haven't even got that option!
if you mean normal audio, you click on make audio cd.