Physx makes about 3 games noticeably better. Cuda... I suspect you don't really know what it is as it isn't really used in games.
*someone chirps in from the audience, it's used in Just Cause 2 somehow*
but while i personally like nvidia, this post was comparing the 5770 and the 5830 which i would also recommend, the 5770, which is the recommendation for half of these question, simply because at it's price point it's simply incomparable, a ridiculous amount of performance for 150 buck is hard to bet
as for the 465, it might be my least favorite card out of this entire generation, i wouldn't get it unless you were dead set against ATI, and didn't want to spend money for the 470
A 5770 can be had for around $150 now, while the 5830 costs $50 more but generally only offers a small increase in performance while also being much hotter and using more power. Right now I don't think the 5830 is worth the price difference, but if you do want something more than the 5770 then I suggest waiting for the GTX 460. I think that will turn out to be a better value than the 5830, or at the least force down the price of the 5830 so it makes more sense.