Low-end cards, which is best?

I'll ask you to list the cards in order of which is better, performance wise, it just has to be better than my 5200 256mb, as something to tide me over untill I get the money for something decent.

7200gs 128mb with turbo cache

7300gs 256mb

8400gs with turbo cache (what the hell is that? something about using your system memory I gather, like on-board vga?)

8400gs 512mb*

HD3450 512mb*

HD2400pro

HD2400XT

*Will I see much difference over the 256mb with these?

That's the list 'cos where I live these are in a similar price range.

FYI the system it would be in will be something like:

E2160
2x1gb DDR2 800
BioStar p35d2-a7

I'm guessing the 8400gs and HD3450 would be the most powerfull? If that's right which of the two has better performance?

Thanks for your opinion.