I think that the first answer is largely correct. Some people want to have power above all else and will do anything to get power, even if the things they do are bad.
In my opinion, one other reason, though, is to get revenge. If you think about it, you can imagine that many in the wizarding world could feel a lot of anger toward the Muggles. The wizards really have more power than Muggles and might feel they are actually superior. Even so, they are the ones who have to hide out and not be open about who they are because they don't want their world to be found out.
So imagine if you had to hide from these Muggles. It would be understandable if you came to resent them and even to hate them. So when you combine this resentment with a desire for power, it is more understandable as to why someone would become a Death Eater.
Far as the above answers are relevant,another reason is pacifism.People are under the impression that Harry is dead,seeing his 'unconcious' body before them.Voldemort has claimed victory,he's got control now.Forget refuting him,but unspeakable things would be in store for anyone who doesnt try and conform to the new regime!It almost goes without saying.
So its like hes giving them an ultimatum to people to join his side,as staying on the good side looks bleak and will be futile.Hes making the first and most easy step of getting the cowards,spineless and most of all,scared people onto his side;the tougher ones can be dealt with later.
I think that no one in their right mind would want to be envolved in something so evil. Unless if of course they are only seeking power. Voldemort will also use his powers to recruit death eaters, through intidmidation.
I think that people would join Voldemort because of many reasons
The first would be because Voldemort promised a better world, for not only wizards but dark creatures, like giants or werewolfs.
Also because people, as Voldemort himself, believed that muggles were inferior and wanted them dead. And they believed as well that the magical kids born from muggles were a waste of space and magical ability.
Another reason may be, that they wanted power, and this power also implied knowin things and spells that not all people knew.
s0me wizards are evil and want t0 use magical powers negatively....take the example 0f dark lord himself ..he was the brightest child howgarts ever had(academically)but he uses his intelligence and cleverness t0 destroy the good and make everything dark....
secondly usually bad ways are really attractive and easy t0 adopt and if some1 want the high powers(temporary)they ch00ses evil....
and talking about death eaters...they actually have lose their minds like voldemort ....:p
Because the person is either torture, killed, scared, a wimp, etc. All negative things. Truth is, nobody want to join Voldemort at heart. It seems like he would win, but then again, the good guys always win.
because they belive that if they help voldemort they will get power.