Hmm,in my opinion that should be electronics and gadgets because we can often see some deals online and also clothes I think is a big one.That should be the top selling products as far as I'm concerned.
I too believe that digital items are still the number one things being purchased, although that could change if we get some more adoption. 
Digital goods are indeed the most sold thing for bitcoin these days, physical items are less more sold for bitcoin these days, that market still need to get more popular.