No, Harry Potter is in Gryffindor. The sorting hat told him he would do well in Slytherin but it took Harry's own thoughts into consideration and placed him in Gryffindor.
The hat thought he would do well in Slytherin because part of Lord Voldemort's soul was inside him. In Harry Potter and the Chamber of Secrets Albus Dumbledore tells Harry that only a true Gryffindor could have pulled the sword out of the hat.
There are many unknown Death Eaters and we don't know all their houses so it is hard to say but there is one known non-Slytherin Death Eater: Peter Pettigrew.
In the Philosopher's Stone movie during the sorting Ron tells Harry: "There isn't a witch or wizard that went bad who wasn't in Slytherin".
However, this line is inaccurate because even though nobody knew it was really Peter Pettigrew who was a Death Eater they thought it was Sirius Black, a fellow Gryffindor (and the only member of the Black family in a house but Slytherin.)
It is more likely that all of them were in Slytherin but there could be some exceptions.
There are a whole lot of Death Eaters, some we'll never know about.
Here's a list of named Death Eaters:
-Lucius Malfoy
-Crabbe senior
-Goyle senior
-Alecto Carrow
-Amycus Carrow
-Antonin Dolohov
-Augustus Rookwood
-Avery
-Barty Crouch junior (Dead)
-Bellatrix Lestrange (Dead)
-Draco Malfoy (Defected)
-Evan Rosier (Dead)
-Gibbon (Dead)
-Igor Karkaroff (Defected and then murdered)
-Jugson
-Lestrange
-Mulciber
-Nott
-Peter Pettigrew (Dead)
-Rabastan Lestrange
-Regulus Black (Defected and then died attempting to sabotage Voldemort)
-Rodolphus Lestrange
-Rosier
-Selwyn
-Severus Snap (Defected, turned spy and was then killed by Voldemort)
-Thorfinn Rowle
-Travers
-Walden Macnair
-Wilkes (Dead)
-Yaxley
There are also other "Death Eaters" who were forced to join under the Imperius Curse, and thus were not actual Death Eaters. Here is a list of some:
-Stan Shunpike
-Poius Thickneese
Some people were not Death Eaters but were allies to them, here's a list:
-Fenrir Greyback (Werewolf)
-Narcissa Malfoy (Wife to Lucius, mother to Draco)
-Quirinus Quirrel
-Vincent Crabbe
-Gregory Goyle
-Dolores Umbridge
Slytherin
Slytherin is one of the school houses from the Harry Potter books.
The Harry potter Group Names are Gryffindor, Slytherin, Hufflepuff, Ravenclaw
The match was between Gryffindor and Slytherin.
What do you mean? The names of the four houses in Harry Potter are Gryffindor, Ravenclaw, Hufflepuff, and Slytherin.
Slytherin
Slytherin.
Harry particulary hates Slytherin.
No, James Potter was in Gryffindor house. Harry's mother was also in Gryffindor.
Slytherin is one of the school houses from the Harry Potter books.
Harry Potter was in Gryffindor, to win the house championship they had to beat Ravenclaw, Hufflepuff and Slytherin. Slytherin were their biggest competition.
The Slytherin house ghost is the Bloody Baron.
The Harry potter Group Names are Gryffindor, Slytherin, Hufflepuff, Ravenclaw
In Harry Potter and the Chamber of Secrets the password was pure-blood.
Slytherin
It is Slytherin's locket.
The match was between Gryffindor and Slytherin.