Pifko's suggestion of getting an On One Pompino is probably a very good one. It has eyelets for fenders and a rear rack, which can be useful for commutting. It had brake bosses front and rear so you can run single speed with two brakes. The frame and fork have room for big and comfy street tyres, which you probably want for such a short commute. You can change the tyres for knobby cross or skinny race tyres in the weekend if you're going for a ride in the woods or on the road. It also looks good with drop bars as well as risers, which is something a lot of bikes don't pull off.
Pifko's suggestion of getting an On One Pompino is probably a very good one. It has eyelets for fenders and a rear rack, which can be useful for commutting. It had brake bosses front and rear so you can run single speed with two brakes. The frame and fork have room for big and comfy street tyres, which you probably want for such a short commute. You can change the tyres for knobby cross or skinny race tyres in the weekend if you're going for a ride in the woods or on the road. It also looks good with drop bars as well as risers, which is something a lot of bikes don't pull off.