"But for pretty much everything I’ve done this past week — basically, my regular work and play habits"
browsing Twitter and writing blog posts?
browsing Twitter and writing blog posts?
What, exactly, do you think people use laptops for? If you're doing something remarkably intensive like encoding video or writing massively scalable ETL code, and you're doing it on a laptop, you have failed at computers.
for somebody who runs a traditional dev stack (eclipse/netbeans + 2+ browsers + compiler/vm + httpd + photoshop + database +++), or a gamer, or a student, a 10 or even 5% performance delta makes a big diff.