out of those three your best option is the GTX 460 but now depending on price range
you might have other options.
and which models in-particular, meaning which GTX 460 and GTX 550 Ti are you looking at.
do not even bother with the GTX 465....
It is all down to preference yes, but the numbers do not lie, the GTX550ti will be slower in all cases than the GTX460.
The 460 shouldve been a 5 series card, its cool, quiet and fast - this was Fermi done right :P - which is why its still wonderfully viable now, and why I have 2 of them in my rig, both overclocked to hell and running as fast as I want them too. Im just gutted about the VRAM on mine, I shouldve opted for the 1GB versions...