The streaming is awesome, if you have the right hardware. And you have to have at least 5 MBps downstream rate for smooth, hi-def viewing. To stream using wifi, you need at least a "g" level router; "n" is preferable.
I recently got the Samsung BDP 3600 Blu Ray player, which is wifi enabled, and has shortcut buttons for Netflix, YouTube, and Pandora. I stream from Netflix at full hi def, onto my 52" TV--via wifi. Pretty sweet. And a lot cheaper than cable.
Netflix is the way to go. It's cheap, and hassle free. The titles available for streaming will continue to increase, and in a few years will outpace physical discs. But even without streaming, Netflix's disc system is still the best around.