For simplicity and value, the Charge Plug is a great single speed bike.
Currently running a flatbar setup, but includes the Bontrager 44cm drop bar handlebars with brake levers and the rear brake caliper should you wish to install.
Flip-flop hub for fixed or freewheel spinning
Medium/54cm(?) - comfortable fit for my 5'8" frame
42x16 ratio
700x32 gravel/cross tires with good clearance