If you don’t need a huge amount of storage space I would risk getting an SSD(solid state drive), faster than a HDD but possibly less reliable due to it being new technology. I think Intel make the most reliable SSDs at the moment.
For HDDs I would go for Samsung or Seagate.
Normal life of a HD would depend on a few things, I think if they are left on 24/7 they are supposed to last longer, I had a Samsung on mostly 24/7 for over 5 years until it recently broke 🙁