Looking for an MP4 Player, Help please

So my wife wants something she can listen too music and watch movies on. She has a Sansa E250r I think is the model. Any way it says that it has video play back but we cant get it to work for the life of us. So the question is which unit should we be looking at? Are Ipod Videos really the best or zunes or what?. We are looking for something easy to use and easy to upload music and videos to, but also not too bulky. Any insight would be awesome.
Thanks ahead of time
Matt