Is it for self defense or just target shooting? For concealed carry?
I went to nothing but Glocks after buying a Smith and Wesson M&P. I had problems with the M&P and was not impressed with the way Smith and Wesson handled it. I wasn't convinced they fixed it so I got rid of it.
Glock is my favorite, it is simple and simply works. I have a 9MM (G26) and 40 cal (G23). I like having both of my carry guns using the same platform, feel, and sight picture. If I had to recommend a handgun for multiple use, Glock is what it would be.