I would turn this trade down in a heartbeat.
Giambi is way better than Sexson, and it's not even close. Have you seen what he's done in the past two weeks? He's finally getting comfortable, and he's on the team scoring the most runs in baseball. Even if their talent level was the same, Giambi will have way more RBI opportunities and score more runs.
I agree that Jaque and Andruw are pretty close, but Andruw is definitely the more valuable player. You may not get a lot more in production out of Andruw, but his trade value and potential are higher at this point.
I'd say Spivey is a better player than Batista, but if you're thinking of using Spivey in place of Kent, I think it's not a good idea. I think Kent is the better second baseman of the two. It's taken longer than expected for him to turn it on after recovering from his wrist injury, but I think he'll come around. Most other fantasy players do too. Spivey has far exceeded expectations, so you're buying him at a high right now. If you think he'll keep it up, he may be worth getting, but I don't think he will. If it was Soriano, maybe, but not Spivey.
Regardless, if you think getting Spivey will be an improvement, you can probably trade Kent for Spivey straight up.
I'd say turn it down.