Need an entry level road bicycle.

I am an amateur cyclist. I explore hyderabad on weekends which may last for 5 to 6 hrs and distance of 50 - 70 kms at  a stretch. I would like to buy an entry level road cycle to explore the city.

Please suggest some options and their prices. I want to keep it low as it is just a hobby. 
I'm 171 cms tall. ( in case needed ).

My blog : 

http://sankrutyayan.blogspot.in/2012/12/happytired.html

http://sankrutyayan.blogspot.in/2012/11/losttheroad.html

And also which is good for road bicycle? fixed gear or gear cycle?