There are several tarantulas that would be good. A Striped Knee is one of them. Also a Chilean Rose and Pinktoe are good too. About all tarantulas are relatively easy to care for.
As far as scorpions, I suggest either an Emperor or Desert Hairy. I think the Hairy is easier to care for than an Emp because you don't have to keep the humidity high for them.
If you decide on the emperor I made a caresheet for them here
http://www.healthyherps.com/forum/viewtopic.php?t=39