Glock 19. It is the best balance between height, length, weight, capacity and performance. It really is difficult to beat. The frame supports 40 S&W and 357 SIG, but the blast and recoil of these cartridges is annoying. This frame size is easy to carry; just get a holster with lots of forward cant.
However, do not underestimate the Glock 26. This gun is quite accurate. Felt recoil is less than that of the Glock 19 and 17. It carries really well and you can use 19 or 17 magazines (with or without a grip adapter).
If you move up to 45 ACP, then the guns start getting chunky. I really like the Glock 21 Gen4 and it is a soft shooter. The Glock 30 had a very wide slide, but the now 30S takes it down to G19 width. However, the magazine extends up into the frame and can pinch the finger during a fast reload.