Quite an expansive request for advice! There are a good number of factors that need to be taken into consideration before an apt answer can be provided.
First of all, what kind of budget are you running on?
Personally, I'd opt for kit which is off the shelf, unless there are specific technical requirements that you may have.
To watch different channels in different rooms is another thread altogether. This depends on the feeds you have to each room (ariel or Sky boxes).
My current setup works very well for me. A permanently situated laptop with XP Media sat on a hifi stack (and connected to the amp), with a S-Video out going to a large plasma. The plasma is also connected to a Sky+ Box, which in turn is connected via RF1 to the laptop (to record Sky programmes) and RF2 to one of the bedrooms (via a Magic Eye).
The only setback is that the plasma and the bedroom tv have to be on the same channel, as I don't have a second Sky box and there is no ariel at this property.
For the best response, I would advise breaking down your request into separate threads. If it helps, I can send you the full schematics of my setup, from which you can decide what aspects suit you and those that don't.
Hope this is of some help.