Going to be a whole different ball game by fall. 45nm cards will be coming out soon, and there'll be a whole bunch of gobbledygook renaming to wade through as they shrink current chips.
I would keep an eye out for a "pure" 45nm card. That is to say a chip that was designed and manufactured as 45nm from day one.
I got burnt on my 9800GTX+. It was supposed to be a 55nm chip, but I am unsure if it truly is, and there's no easy way to tell. Asus is being evasive in answering my queries.
When it comes close to trigger time, do all you can to ensure the card you get is the one you want. These idiot companies and their idiot renaming / rebranding are just plain devious, if you ask me.