Personally, I like the first photo the best. I have to say, the way it's sitting makes it look more like pet than a wild animal. It looks like many of those were taken on cloudy days, which to me makes for the best light. When it's bright and sunny you end up with high contrast. I definitely suggest a long lens, it makes shooting wildlife much more exciting. You seem to be making your lens work well though, good job!
Be careful with bears! I've never really felt like my life was in danger around a mountain lion but around a bear, definitely. Well...and a moose! Long lenses save lives. Where in Colorado are you?