8GB of RAM causing BSoD

Seriously, read up on 32 bit.
32 bit can't handle more than 4gb. It's just a limitation of 32bit.
It's not defined by Windows.

Google PAE (Physical Adress Extension) plawks. Server 2003 Datacenter Edition can handle 128gig on 32bit (and that's a marketing restriction again) 256gig should be possible. Linux can too (but I hear it's a little buggy)
Why do you feel the need to correct people when you have no idea what they are talking about?

For people unable to get exactly 4 GB RAM (like, they get 3496 or something), aren't they able to drag it up to 4 GB?

In theory they could but it's locked down - so no.