hamsters love porridge, wheatabix, rice pudding etc. with milk. A lot of people suggest that hamsters can be lactose intolerant too and say that they should have kitten milk or lactol, but some people find that normal milk is okay in small quantities!
Mine like cheerios too, shredded wheat, readybrek, anything like that Joe14!
If you do a search for lactol on the forum I bet you will come up with loads of ideas