[mythtv-users] Going HDTV! Assistance REALLY appreciated please

[mark]

I have been on 18.1 ( ATRPMS FC3 ) for a while and working great.
Here is my situation now, advice or information please?

Machine: Celeron 2.4 300 Gigs space, FC3, DVI Nvidia card going into 
DVI - HDMI HDTV
TV: Toshiba 52HM84 w/ HDMI input from above machine
HDTV source:  Bell expressview in Canada with DVI/component out

My questions are these:
What HDTV card is best and where to get it?  How about the HD card from 
http://www.pchdtv.com/ ( pcHDTV™ HD-3000 ) will this work OK?  Is there 
an easier choice?
Is my celeron 2.4 enough with 512 Megs RAM for HDTV?
How do I control the HDTV box to change channels from Myth?
What Xorg.conf refresh / resolution rates should I use? I do not want 
to damage the new TV and want to get the most out of it too.

I will continue to read/research, but assistance/guidance really 
appreciated.

Thank you!

Mark