Hifi set normally can only give you at most 2.1 speaker system and cannot give you Dolby Digital or DTS surround sound. But many of these are cheap and can give you reasonable audio reproduction. Home theatre will give you 5.1 speaker system and therefore the surround effect can be quite complete. But if you want one that can have better music reproduction, that can be quite expensive.
For Hifi set with DVD player function, I suggest you check for Onkyo, for home theatre system, try to take a look at Samsung, Sony and Philips.