I don't think Giambi is a fine replacement at all.
The Yankees paid WAYYYY too much for him. Got even less out of it in the postseason and lost a clubhouse leader, standup guy and proven playoff performer to boot. Way to reward the guy who worked hard for you and kept the series going last year with what I think will be my most memorable HR ever.
It's tough being a Yankee fan in the buying spree times. The players I like have always... and will always be the talent they nurture (who then does deserve their money) Jeter, Williams, Soriano and the journeyman guys like Paulie and Tino. That's who keeps me around, not Jason freakin' Giambi.