I've cut down several by myself with my handy dandy 20'' chainsaw. Wish I had a "bigger one"
I found even the really tall Pine trees in my area are easy to cut down and saw up. (still a dangerous job) I've actually used some of the Pine logs for outdoor chairs (stools) and a few other uses around the barn. Hardwood trees (like some of the Oak varieties) are a lot harder and much more dangerous to cut down (IMO). I cut down one (once). I'm sure it was 50 to 60 feet tall, maybe more, and probably almost that wide (tree branches tip to tip). Never again.
A couple of years ago, I had a local tree service cut down 3 Oaks that had died. He had a crew of about 4 guys and finished the job in about 3 hours. They cut them down, saw them up, pickup all the branches, and hauled them to my timber pile. (Most folks out here have dead wood piles somewhere on their property) He charged me $750, which was cheap IMO. Also, I made sure I hired someone that was insured.