taking a step back; what was the best upgrade you've purchased for your pc, EVER?

this week i realized that its about time for me to do a desktop system rebuild.  prior to the last year and a half, i had been on an upgrade rampage in regards to my desktop pc.  i initially built my very first desktop system back in 1998; it was an AMD Athlon (Slot A) 999mhz cpu w/ 512mb pc133 memory, a whooping 20gb harddrive and dvd/cd-rw combo drive and cost about $400 to build. 

through my upgrade bender i went through about 12 different computer cases, 10 motherboards, 6 video cards, and 3 monitors.   so with all of the components i went through, what was the best upgrade? 

my Dell 24" LCD Monitor hands-down!



i don't know if you have ever used a 24" widescreen monitor before but lets just say once you do you'll never go back.  i have friends who own/use crappy little 15" crt monitors or a 17" lcd and it baffles me on why one would not upgrade the one thing he/she uses each day?  if you have to use it or do use it on a daily basis, why not make it more enjoyable and better on the eyes?

i've had my dell for about 2 years now and would consider it to be the best pc upgrade ever.  prior to my dell 24" widescreen, i had a very decent standard 19" Lcd but it still wasn't enough desktop space for the stuff i was doing (photoshop, video editing/mixing, gaming, geeking).  my work 20" widescreen just doesn't seem the same, however having two of them does help though... :)

so, whats your best/favorite pc upgrade you've done? feel free to share in the comments. ;)