One of the Toyobaru twins, the VW GTI, and the Civic SI are all extremely easy to learn on. Their clutches are light with a large engagement zone. The Mustang (5.0) would be a little more difficult to use only because its engagement zone is smaller and higher up, but none of these are hard to start on in the grand scheme of things. Modern stick shifts are stupidly easy and near fool proof to use after maybe 15 mins to a half hour of use.
E92 335i: Space Grey|Coral Red|Aluminum Trim
Future Ride: 2015 Mustang GT Premium |Guard|401A|PP|Recaros|6MT