Well, the '800MB' figure is rediculous at any rate. The thing is, most postings about this memory hog have mentioned a very specific build. If anything, that build could have developed a memory leak, or else this would have been public knowledge for quite a while.
I find it strange that Vista has been in Beta 1 for months and months, and only now somebody comes out and says "Oh look, this is using 800MB of ram."