You have to add a bigger HDD and loose the consoles warranty in the process to accomodate several games.
Not really true at all. Certainly not for xbox.
Yes, PC parts have 1-5 years warranty and within atleast one year the store has to handle the exchange for a working part.
Emphasis on the 1. About the only thing you'll get with more than 1 year is a hard drive or some video cards. And while the store is compelled to exchange for a working part, they are not compelled to do so quickly, they can take up to 90 days to identify if the part is eligible for replacement if they like and then half the time they don't have an exact replacement so you'll wind up with something else. Xbox repairs are pretty pain free compared to getting an etailer to do a warranty exchange.