i have a sony vaio at home that's been running for 3 years now. it fell so many times that the actual ports on the sides are shattered, except for one usb port which i connect my ipod to.
i have a dell vostro at work which i'm posting from now. about a year in, works as good as new.
i also have a dell t3400 workstation at home which i just had to re-install because it was giving me the blue screen of death after installing norton from comcast. those fucks.
but it runs like new now too.
i think it's unfair to say "dell sucks" or "macs rule". just goet a quality dell, and you'll be fine. a 300 dollar "netbook" won't give you the supercomputing powers you expect, but i bet a $2,000 dell will.
you get what you pay for.
also, diecide, just re-install your computer, start fresh. i bet it runs like new again.