I don't know what to think about this trade, to be honest.
In the short term, I'm not sure it benefits the Nets. Deke is an enforcer in the paint, but it really leaves them reliant on Richard Jefferson and KMart to step up and provide some scoring punch. They could be the best defensive team in the league with those two guys, Deke, and Kidd. Also, Deke seemed to have noticeably slowed down last year. He posted career lows in shot blocking and rebounds, and that's his game (lol, and those totals were a bit inflated I think because of all the times he blew up Curry and Dillybar last year

). I like the D, I'm just not sure where their points will come from. Maybe they could pick up a guy like Lamond Murray to help them out there.
In the longer run, they got rid of Van Horn, who while young and talented, has an absolutely ridiculous contract and who curled up into the fetal position when the going got tough last year. They get salary cap space sooner, and if they can entice kidd to stay and and then pick up Garnett or Duncan next year maybe they've got a future.
For the Sixers.... well Larry Brown seems to enjoy blowing his team up every year, and maybe this one will work out. McCullough is a more than serviceable center, I have no problem with the deal from that perspective. The Sixers are getting a young, decent center at an ok price (at least for a center).
Then there's Van Horn. On the plus side, he adds scoring punch. The real catch to me is that he also seems to me to be exactly the kind of player that will drive Brown up the wall and the player into his doghouse (to wit, Jalen Rose, Tony Kukoc). Truth be told, I think Jalen and Toni (when healthy) are both better than Van Horn. I predict Brown will end up wanting to kill him. Problem is, Van Horn's contract is widely viewed around the league as a white elephant... who will he eventually be unloaded on?
Best case scenario is that Keith Ds up, and they've got a lineup of
McCullogh, Coleman, Van Horn, AI, and Snow. That's a very good defensive team, aside from Van Horn, and very big, physical team aside from AI. Aside from Aaron McKie and Greg Buckner though, their depth leaves a lot to be desired, Their depth leaves a lot to be desired, especially when their starters are somewhat brittle.