Laptops
Laptops have never been consistently easy to upgrade. My current (and ancient) Dell Inspiron 8200 might be about the easiest I've ever encountered.
Memory trapdoor: 1 screw.
Hard drive: 1 screw.
Optical drive: 1 screw.
Modem/wlan slot: 1 screw.
Not that these are things which need changing very often, and "difficult to upgrade" wouldn't stop me from buying a laptop.
Having to take it to the dealer for a battery replacement *is* a deal-breaker though.