Youre first two shots came out nicely, the last two are due to harsh sunlight. If the flash went off on your camera in addition to the sun that can wash out the pic...the last one you were shooting into the sunlight. Keep your light source behind you whenever you can unless you are looking for a silohette effect.

I've been prowling carmax and autotrader looking at GXPs...gotta say there are some deals to be had right now. I wish I was able to jump on one of them.