I'm a little late to the party here (I just voted) but I wanted to throw in my two cents worth...
When I made the decision to purchase a Surface RT I also decided to finally treat myself and get the maximum tablet options. I figured if I was going to spend the money for a premium machine (something I've never done before, I've always built my own desktops and bought budget portables) I was going to go for it all. So yes, if I had it to do over again I would do the same and buy the 64GB model.
(Side note: I didn't opt for the spendier Type cover because I liked the concept of the Touch cover more, so I guess I went a bit budget there.)