2 Newbie questions

[Jaynru]

I am thinking about upgrading to a blu ray player. not sure which model I favor as I have done little research. I have read a few things that make me uneasy about purachasing a blu ray. I also have a 5.1 Sony System with optical audio cables hooked up.

My current TV is a Sony 57 inch widescreen projection style TV. Approximately 3 years old. I have HD cable via Direct TV and the picture is phenominal, even for a projection style TV. Watching TV in HD has a better picture than my regular DVD. I also have a 5.1 Sony System with optical audio cables hooked up.

1) My tv only is 1080i. How much am I missing without having the ability to watch Blu ray discs in 1080p vs 1080i? Is it worth me making the upgrade and not having 1080p yet?

2) I do not have a HDMI input on my tv set. I currently use a HDMI wire from my DVD player that converts to the input (DVI)? I can't remember what it is called, but it is white and looks like a typical computer moniter jack. Would that wire allow the 1080 upconvert for regular DVD's? Would I be better off using monster cables or svideo?

Thanks for your time and help. I truly appreciate it.