1) no, watching streaming video is not going to take that much bandwith to be bottlenecked by pcie 1.0 slot
seems to get good reviews barring the guy that dident get his rebate and another without a crossfire bridge.
looks like it but im no expert on tvs.
Note: if you are going to be using this card for just watching hd movies then you might want to look into getting an hd 5670. for power consuption, bitstreaming Dolby TrueHD and DTS-HD Master Audio and such if those features are what you use.
edit: forgot linkyhttp://www.tomshardware.co.uk/radeon-hd-5670,review-31787.html