Let's fantasize for a moment that the Yankees have to eat the rest of his contract or are able to work out a buyout with him that gets approved... and that the A's could get him for very little money.. Would you welcome him back?
This question has at least two components. The first is whether you could forgive him for leaving the A's for the Yank-me's, and forgive him for his steroid past. The second, and i think more interesting part, is how do you view his future as a baseball player? Do you believe his past success was primarily due to steroids, that his body is too damaged from years of steroids and living hard, etc.? Or do you think/hope that he is capable of being someone that can hit for power and average again?
Would you enjoy watching him play?
Of course, there's also the dimension of where would he fit in -- in the past, he's injured too often to count on for an everyday first baseman, and we've got durazo for DH, and hatty already at first.
My own answers: I can forgive him and would enjoy watching him as an A again. I think he can get healthy and succeed without steroids. A recovered Giambi would be a great presence in the lineup.
(and a side question: how long are steroids detectable; how often would you have to test someone to know that they're not taking any?)