I'm bewildered by all the different choices especially in the semi auto realm. If I go semi auto, I would be looking for a home defense gun.
There are certainly a lot of choices. I would suggest a Glock semi-auto in either 9mm or 40 S&W. I prefer the middle sized Glocks such as the M23 in 40 S&W. Hi Points are probably the least expensive. I hear they are a good value and generally are reliable, but I have no actual experience with them. Any of the Rugers would be a good choice.
In a revolver, you will pretty much end up paying more for the good ones. My suggestion there would be a mid sized steel framed gun like the S&W Model 10 (38spl) which can be found used in very good shape. The Ruger GP-100 is an excellent choice as well in probably a 4".