Updating a classic? Sweet. See this thread
http://www.bikeforums.net/showthread...+vintage+frame. To put a modern 9 or 10spd group on it, you'll probably have to have the rear triangle spread. It's called "cold setting" but that's just a fancy term for "bending the stays." Sheldon Brown's website shows you how to do it yourself, but I felt alot better about spending $35 to have a local framebuilder do it correctly.
And, as you say, you'll want new wheels and shifters and all those other bits. I suppose you could do it as cheaply as a couple of hundred dollars all the way to several thousand if you went all Carbon Record.