what to look for before buying a dvd player

basic dvd players are single disk players & comes with a remote with average functionality. High end ones have differrent advanced features. Multi disc capability is one such. A universal remote if supplied will take care of the need to use multiple remotes.

Audio output is also needed to be looked at. Some players offer surround sound (like for example 5.1 channel players). DVD player with an inbuilt amplifier is capable of being connected to speakers directly.

Coming to the video part progressive scan offers flicker free pictures (like in the movies)
S-video or component cable connectivity offers slightly better quality of pictures.

region code of the dvd player need to be looked at as a region locked player can play of the same regions only. Multi region players are capable of playing dvds of any region.

DivX a relatively new compression codec is supported by some players increasing the repertoir of playable formats.

Type of DVD/cd (like dvd-r, dvd+r etc)playable should also be looked into. The more the better

mp3 playback or playability of picture files are a definite enhancement and most of the players support them.

USB connectivity is a very handy options.

other advanced features are bookmarking (that allows to store location of favourite scenes) and resume capbility (the capbility of playing a disc from where it was stopped durin a previous session of play) are also very useful