Minimum card for 1080p playback

[Clum]

I upgraded to some 26" monitors last week and gave on of my old 22's to my sister who is now using her pc as her bedroom tv. She wants me to put a blu ray drive in for her but as her graphics card is an old ati x600 playback it too choppy to be watchable ( i tried playing a few x264 vids to check). What do you all reckon the cheapest card is that would play back 1080p smoothly? The rest of her specs are of the P4 era but cpu and memory usage while playing back the x264 are only 50/60% so a replacement card should do it. Not fussed if nvidia or ati but just looking for the cheapes one possible that will do the job as this is all it will get used for....no gaming whatsoever.

input appreciated!

 

[Musty Pie]

my recommendation is this:
http://www.overclockers.co.uk/showproduct.php?prodid=GX-184-SP&groupid=701&catid=56&subcat=1274

 

[Chong Warrior]

This card would be better value: http://www.overclockers.co.uk/showproduct.php?prodid=GX-177-SP&groupid=701&catid=56&subcat=168

 

[Ducky Spud]

Ive got an Nvidia 7300LE in mine until my 8800GTS arrives in the post. But that plays most high def movies from my hard drive alright, though one or two have "skipped" in the odd place, most seem to work fine. Can get one easily for less that £30