I would definitely start with something simple like a basic four bar. If you're feeling like a little more height than a basic four bar offers I'd try doing something like
217 and 229 did in '05. Don't try something with many of degrees of freedom like 75, 537, and 1251's arms this year, I speak from experience on this, our robot this year had a 5 degree of freedom arm, and we wasted a huge amount of time making it, and wiring it, not to mention difficulty controlling it. If I were you I'd build an arm with about 2 degrees of freedom maximum.