Is it acceptable to use address labels for wedding invitations?

Address labels should not be used, envelopes should be hand addressed.

Traditionally the envelopes should be hand addressed, that's what I did. My cousin's wife printed hers in a fancy script-like font and it looked very nice. If you choose to go against the "norm" and use address labels, use the clear ones like this:

Staples.com®. that was easy®. (http://www.staples.com/webapp/wcs/stores/servlet/StaplesCategoryDisplay?jspStoreDir=Staples&catalogId=10051&productId=120822&cmArea=SEARCH&interceptedCatEntryId=120822&identifier=BI35121&langId=-1&storeId=10001&ddkey=StaplesProductDisplay)

Or decorated ones like this:

Staples.com®. that was easy®. (http://www.staples.com/webapp/wcs/stores/servlet/StaplesProductDisplay?&langId=-1&storeId=10001&catalogId=10051&productId=85572&cmArea=SEARCH)

You can also find decorated labels with wedding-themed pictures on them (doves, hearts, flowers). I'd avoid the plain white ones - it would look too business-like.

Handwritting is preferred.