No gaurentte on life expentency, Just pick one that has the LOWEST dissatifaction percentage at New egg.
Yes larger drives have a higher performance in general. But NOT ALWAYS.
Performance is primarily based on RPMs, and the density of the magnetic domains, and what percentage of the drive is used. Last two relate to how much data can be stored in the outer edge of the platter where angular velocity is highest.
To be honest its a gamble no matter what. I have had 5400 rpm drives fail after a month, my ssd failed after 6 months and that doesn't even have moving parts. I have had a Raid 0 with 2 seagate F3 1tb drives for almost 2 years though now and no issues. No one really knows. They do say that faster spinning drives and larger capacity drives fail more than slower, smaller ones though.
hmm ok thanks for the replies. What do you guys think i should buy, I am mostly going to have installed games, maybe the odd mmorpg, music, game installer backups. What size? I'm thinking 1tb I guess. But it's only £40 more for a 3tb?