OK depending on if you want to spend more money the HD Tivo will cost you a bit. Yet the Comcast box is like $10.00 a month. In my area they are giving the 2 tunner box so you could record to items or watch one record the other. What you will be missing is the great Tivo guide I have 3 Tivo's in my house and I do love them. I am not that much in love with the HD Tivo due to cost and no Tivo to go on it. We only have 1 HD TV in the house so as for now we just use Tivo. I will face the same questions you have once I change the main tv to HD by then I hope Tivo 3 will allow Tivo to go....

PS I even have a Tivo 1 with a life time membership.