I've actually had quite a different (positive) experience shopping on Amazon with regards to warranty. I know the word warranty gets thrown about quite abit here and i must stress that MY experience might not be the norm and/or apply to you, but being polite, friendly with the service staff certainly helps alot.
I won't name brands for fear of getting the principals in trouble with the local disty but most times when i've had something break, i e-mail them directly to the head office, and more often than not, they would send me a replacement brand new unit, straight to me in SG, without even asking for the item back. Of course support your warranty claim with pictures, details of what happened, etc and they will most likely be happy to help.
Warranty is important especially for PC components and most brands would want to be 'friendlier' to their customers.
Just an example, i bought a BlackBerry from a UK website, phone broke within 3 months. I e-mailed BlackBerry and they told SG service centre to issue me a brand new local SG set. Whole procedure was hassle free and took 3 days.
YMMV though so do your own due diligence and make your own decisions. Ultimately, it is YOUR money so weigh the risk.