Just to clear things up:
Downstairs in my house, it stays VERY cool, probably only 65 or 70F as we keep the windows closed and the shades down, and then open them at night. It's my upstairs BEDROOM that will go to 100F, mostly because it's got 3 skylights. I've tried closing everything UPSTAIRS durning the day and it gets even hotter! So I just keep the upstairs open and the downstairs closed.
But yes, I do want to get an AC for upstairs, and I might even look into some cooling upgrades for my PC -- the video card overheated at 150F last night and locked up while playing Doom 3. (It was still about 80 - 85F in the room.) Nothing broken though, it just stalled for a minute. Whew! It's liquid cooled and has monster of a heatsink, but I guess that wasn't enough.
I'm adding another front-side case fan later.
Sounds exactly how my house is.. downstairs is very cool.. but once you start walking up the stairs, more towards my room, you can just feel how much hotter it is than the rest of the house.. it can get somewhat unbearable, but at the same time the PC doesn't really overheat. I live in Roseburg, OR and yesterday it was like 97ish and my vid card actually hit mid 50s c for the first time ever I believe. I overheard my mom saying that at home depot they have this like window tint stuff that is supposed to help keep heat out. She said it was inexpensive.. so I'm going to go check that out today.. you could maybe look into it as well DJ and adding a fan never hurt