Hyderabad is a best place to experience people from entire country this is well explained as the north of south india and south of north india.
City is a mix of old city and new sky touchin buildings. City have ancient monuments like charminar, palace and thomb all these place took one day to visit.
One full day goes to Ramuji filmcity visit. Ah the way indians like bollywood the ramuji catter lot of memories from bollywood.
The osman sagar lake with a huge budha idol in the centre is a nice place to visit in the evening. The lake is surrounded by lots of food courts and fun places like limbuni park, prasad cinemas snow world laser show etc.
For foody speciallly non vegetarians hyderabad offers a lot of dishes thats difficult to find in any other place with same spice and flavour. If you are here dont miss hyderabad biryani, haleem, paya, shorma, sawarma, kurbani ka meetha, dilkhush osmania buiscuit and some typical sweets near char minnar area. Also try hyderabad chai its easily availlable at small tea stalls in entire city.
I recommend some nice restaurents with nice veg and noveg buffet and cusines like paradise biryani, bikanerwalla, sia, madras cafe house.
Also if you are in hyderabad just meet some local from hyderabad and talk to him in hyderabadi hindi you will blow your head laughing.
Hyderabad is also centre of tollywood and residence for lot of popular people.
I guess is not only a good city for a trip but I guess is one of the best city in india to live for people from all different religions and community!