you don't need Xfire or SLI for an HDTV. most mid to high end of the current generation can easily handle the majority of games @ 1080p. if you're looking for extra oomph at 1080p, all you really need is a card with 1GB of video RAM on it.
See the struggle of the faithless lot as they negate their time
How low to sink to the depths of their frame of mind