For the most part, component and HDMI are pretty equal in terms of quality. In exchange for some DRM garbage, you get your audio carried over the same cable with HDMI. All HDMI is, is DVI + digital audio + DRM garbage. It's not some new system, it's just combining two existing ones into a single cable, and throwing in some DRM garbage just to punish people who actually buy DVDs and what not. I think both Sony and Microsoft have sold out to Hollywood (I suppose Sony is part of Hollywood) and crippled the playback of HD-DVD or Blu-Ray movie discs when the signal isn't going over HDMI. I forget the limits offhand, but if this sort of thing is of any concern to you, it might be worth researching on your own.
In any case, I would be sure to verify just what kinds of inputs this TV you're planning on getting has. That way, you can plan accordingly for later. If it doesn't have any sort of HDMI inputs, then it kind of solves that whole issue rather quickly. If it only has one set of component inputs, then you might want to look into a device known as a source selector. It's a device that lets you share a single set of inputs on a TV with multiple devices... Such as an Xbox 360, PlayStation 3, and a DVD player, all at the press of a button. It's come in quite handy for me with my Xbox, PS2, and GameCube all hooked to my monitor via S-Video.
Seeing that Christmas is coming up here shortly and there are rumors of a $399 PS3 floating around, I'm looking to purchasing a ps3 to sit next to my 360 here in the short future. I just have questions concerning the hdmi/component cable question and headphones. I plan on playing my system on a 55" LCD Sony Grand Wega. I'm fairly certain that it has an HDMI input in the back, but I also believe that it can only go up to 1080i. So my question is concerning cables is, is it worth the money to ante up for an HDMI cable or would I still be fine with just a component cable? Also, which cable seems to work the best for both kinds? And along with those questions, how do I communicate with the players online?

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