Actually its always better record multiple voices on 1(or alteast only a few takes). It never sounds as good multi-tracked and you loose the interaction between the different people singing. Of course for most people this is impractical, but if you can its best to use a real choir.
Brando - thanks for watching. Some people won't have any use for this, which is understandable, but for me and I assume others this could be useful.
batsbrew - recording and mixing 64 tracks of vocals isn't my idea of fun, but to each his own.