There's plenty of software out there to let you do this, you don't need Media Center. Media Center is designed more to be a central repository for all your media and is better suited for a home-based computer, rather than a notebook.
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I am planning on doing the same thing. I know Roxio has a Media Creator that seems like it would help in this but Im not hip yet on what everyone is using other than Mac people are using IDVD.
But read this article about some software that does some of what Media Center does and perhaps better.
I think though all you need to put your VHS tapes to DVD is a convertor for the VHS machine out to firewire (to get into your hard drive) and some video editing program. Again, I dont know what everyone is using yet. I dont think you need Media Center Ed for this though.