+1 5850, its ~15% more powerful than a 460 1gb. And out of those two, I'd go for the sapphire.
Though the 460 overclocks perhaps a little better than the 5850 does, but I am pretty sure a 5850 overclocked still beats a 460 overclocked.
is so hard to decide because as you said physx is a good deal with ndvidia, but i am also deciding for ati because my mobo (ecs p55h-a) could have crossfire so... ha!!! i hard to decide, right now i play starcraft 2 and battlefield...and my current card is an ati 4850 512 mb
Your resolution is extremely low by today's standards. For 1366 x 768 you should save some money and get the 768mb version of the GTX 460. Or an HD5770. Both are overkill to be honest but a reasonable amount. Above that you are just wasting money basically unless a monitor upgrade is in your future.
the psu is a concern i will need to buy one, before getting married i need to buy a 1080 monitor jejej... preparing for marriage... why do you expend that much on some computer stuff..bla..bla jaja i want to avoid that...
The 5850 is a great card. I'm thinking about upgrading to it now that its around the $150 mark here in the states. Thats a heck of a price for something that was $300 not to long ago. I haven't done it because my 5750 is fine for playing TF2 and L4D2 at 1680x1050, and I need a new CPU over a GPU. I'm still on my E6600, a dual core chip. (OCers will scream when they hear this. I have an X38 board, the E6600, and the Hyper 212+, and the CPU is at STOCK!)
Yes, you need two 6-pin PCI-express power connectors. You can get a power supply that has two of them. Just check the product details. They do sell adapters separately if you PSU does not have the right power connectors.
I'd check the details of the product to be sure. It's very frustrating to get a new card, and then not be able to use it until you get the correct adapters. I had that issue with my 6970 not coming with an 8 pin adapter.