So im building a home server and was wondering what hard drives i should buy for the server (windows / i7 / 100mbit connection).
Ive been using Seagate before on my gaming computer and the quality on those kinda sucked (many of them broke down after a few months). Are there any other harddrives (WD?) that is better and that doesnt break down often? Im not interested in any raid, just plan simple internal harddrives that just works 
The best hdd is one that doesn’t break. Not even joking… many people (incl you) will say Seagate are rubbish, but you’ll get a crowd saying WD, Toshiba, Hitachi and the rest are just as bad.
So get one from a reputable brand, that you can afford, that has the right capacity, and hopefully you’ll not be affected.
Since you aren’t interested in anything except which disk I’ll refrain from writing anything else.
You must distinguish between drives where you store your movies on
and drives where you store your Plex data folder
#If you don’t use RAID:
for your movies, you can use those large ‘archival’ drives they offer now.
They are not particularly fast, but that is not necessary - even for full BluRay rips.
For your Plex data folder, I’d recommend you to use the fastest drive you can afford.
This may mean nowadays a SSD. But a faster ‘spinning rust’ drive may be just enough too.
If you are using the DVR feature, I recommend you to put the library folder into which you record on a faster drive.
#If you use RAID:
use drives which are certified for ‘server’ and ‘RAID’ use.
I store my movies and music on a WD Red (NAS) drive, size depends on the number of files you plan on storing. Playing the movies from the Red drive works fine. My backup data is also on a WD Red drive.