Let me just get this out there: To compare the newer series GeForce cards with one another, you need to look at the last two digits of the card's name. For example, in the GTX 460, the important numbers are the '60' ones. The '4' indicates the range or series of cards only, whereas the '60' shows you what type of GPU it has on it.
Now, because the GTX 460 is a newer model than the GTX 280, it will outperform in terms of stability and heat dissipation. It will, however, cost you a bit more, and the GTX 280 would still win if you compare FPS in most games.
The newer GTX 460 Cyclone from MSI is an exception. This card comes factory overclocked (thus the OC in the name) from the core GPU speed of 675MHz to 725MHz. This increases its performance dramatically, and makes it one of the most money-efficient cards in the GTX series, in some cases (proven in real-time tests) outperforming even the GTX 480.
Furthermore, the card comes fitted with an aftermarket cooling system (this is the Cyclone cooler), making it run a lot cooler and up to 15.7% quieter than generic GTX 460 cards. Also, as it runs cooler, it allows for further overclocking with the VERY user friendly overclocking software included in the box, called the MSI Afterburner software. This can let you tweak the card to perform as good as a GTX 480 and even better, at the same temperatures.
The card has, however, a few downsides. Firstly, the twin-heatpipe design used to cool the card very well, sticks out to the top of the card fairly far, and will require a bigger sized box. It also asks for two 6-pin PCI-E power connectors, one more than some of the lower class PSU's support. Also, being an overclocked card, it will lose value quicker than the generic, and even more so if you further overclock it with Afterburner. It also only has one HDMI and two DVI outputs, and supports a maximum of (very disappointingly) only two monitors.
On the plus side, I bought mine in South Africa a few days ago, for R1,949. This amounts to about £163. Bargain? I'd say!
So, no, the GTX 460 Cyclone OC probably won't beat a GTX 280 in terms of sheer performance, but if you need to pick between a GTX 280 and a GTX 460 to start off with, I'd go with the GTX 460. And if you can get a bargain like I did, all the better!