Wait before netbooks comes with new intel cpu technology specifically for multitasking and doing several things at the same time. The prices of those are still high so the the best choice would be to wait. You wont have a good time multitasking with one of those intel Atom cpu's, same goes for watching movies.
My advice is either wait or raise your budget. Im sure you will get disappointed if you get the Model I8B11D4 with the ATOM processors with a hope of multitasking, watching movies and downloading much.
Intel i7 920 2,67 Ghz clocked to 3,22 Ghz
6 Gb Ram with Velociraptor 10K RPM system disk
Dual Boot Windows XP 64-bit and Windows 7