Questions re: graphics cards and network devices for multimedia streaming

[LookinAround]

Here’s my specs, some background info and questions:

• Dell Optiplex 360 Desktop
• Intel Core2 Duo CPU E7600 @ 3.06GHz
• Dual boot: XP SP3 / Win 7 Professional
• 4GB RAM
• Broadcom NetLink Gigabit Ethernet
• Speed test info
  

I’m planning to buy a couple new TVs (one of which will also double as my computer monitor) so have some questions/soliciting advice about

New Graphics Card
Recommendation on a new graphics card for the Optiplex 360 Desktop?
> I assume i want HDMI output?
> I’m not really a “gamer” but do stream a lot of videos / movies / music etc off the net (e.g. Netflix)

Picking network devices

• Any practical experience or insights in choosing preferred method / equipment to connect to Netflix or other streaming supplier? For example: Comments on pros/cons of buying a Web app (e.g. Netflix) capable TV vs. buying a TV and getting a separate, external Web app capable device (e.g. a capable Roku or Wiii or blueray player)
  
• I’m guessing I’ll get better video streaming quality (especially HD video) if I connect my Web app capable devices using a wired connection vs. a wireless signal. Anyone have any info or data on quality of streaming HD video over wireless vs. wired?
  
• Any practical insight or considerations in choosing between using powerline ethernet adapters instead of running new wires?