The Cable/Sat Free project

So after a discussion with my wife about how expensive Sat has gotten and how expensive cable already is. I decided I wanted to find an Alternative. So we talked about Roku HDTV Antenna, upgrading the HD in our HTPC to a 1TB or bigger and the price of it all.
we are currently spending about $70 a month with Dish Network. For a while in the past we used an home made HDTV antenna, and it worked well. The concern we have now is that we have a 2 year old who loves Nick Jr. Programing and we our selves have become used to Food network,Travel Channel, and Bravo programing.
My questions are:
What do you guys think of Roku? Is Roku worth it, with out Netflix? Is there an alternative to Roku that I should be looking at?
Is there a certain HDTV Antenna that I should try to get?
Is there a way for me to get any of that programing with out Cable or sat?
What about specific HTPC Software? Any recommendations?
Recommendation on a HTPC Keyboard?
Any other Info?
thanks a ton for the info