there are many ways to buy or DIY method for your HD HTS,but first what is your room size and budget then things will follow.
1. you have to decide first what type of display you prefer either TV (LED/OLED) or prefer a big display like the projector.
2. a decent AVR (audio video receiver) many popular brands are available like denon,marantz,onkyo,yahama etc..again depends what is available at your place and which has a local service center or even you can go for online option but i prefer the former.
3. speaker systems either 5.1/7.1,you can get a complete package or buy sub separate with a matching Mains,center,surround.
4.Correct the room acoustics there are many threads in hfv ..
First and foremost, what is your budget, room size, music/movies preference etc.?
For lower budget, there are some packaged home theater systems available in market in which you will get a Blu-ray Player with Amplifier + Speakers. Sony BDV-E290
But it is not recommended.
If you have good budget then you can go for separates. Like; AVR: Yamaha, Denon, Pioneer etc. Blu-ray Player: Sony, Pioneer, Oppo etc. Speakers: Pioneer, Wharfedale, Dali, Polk Audio etc. Subwoofer: Velodyne, SVS, Wharfedale, Polk etc.