Depends what you use the computer for more. Widescreen is great for videos and for multitasking things like messenger services beside an open web browser as you dont have any real side scrolling. However for word it can be a bit of a pain as they are not as tall but much wider. So it is swings and roundabouts. Personally I prefer wide for what I do.
14) Intel Quad-core processor
Do you need a ferrai? Pretty simple question to answer really. Why waste money. Upgrade to it is easy in the future when it comes down in price.
15) LAN cards
For the money you plan to spend it is 99.99% guaranteed.
13) Use of multiple hard drives
More heat yes. but not too much more. More use, yes backups to a second drive mean if the first goes while it gets replaced you dont loose the important files. Plus in a RAID configuration it means you actually get a faster drive speed.