The Glock 19 is arguably the long-time undefeated champion of this category. It has a long track record of durability and reliability used by countless law enforcement officers across a myriad of agencies as a uniformed duty weapon and a plain-clothed concealed carry weapon. That reputation has carried the pistol into tactical fandom making it an extremely popular choice for the armed citizen. With the marketshare it holds, the aftermarket support borders on obscene. It would be incredibly faster to count the number of accessory manufacturers that don't offer products for the G19 than those that do. That means there are nearly endless choices for everyone to customize their Glock 19 to suit their needs and style.
Whether you're a Glock fan or a member of "the grip angle doesn't work for me" is irrelevant, it sets the bar that all other pistols in this category are measure against. Unless there is a significant hand size fit issue, one can't go wrong with a Glock 19.