Most of the time, I'm trying to work on video projects, which definitely can't be done retro, at least not easily. I suppose I could go old school with a toaster system but I tried a friends and found it crazy compared to modern editing in digital... Used to have alot of old analog gear, I sold it all. Now just a tiny great quality digital video camera, a pc, and me are making cool stuff...
Unfortunately I can't afford a mac and final cut so I'm using windows so I need alot of horsepower due to the very ****ty windows video editors, not complaining, things work, just some stutter occasionally while trying to edit, even on a quad core....
For everything other than video editing, I use a dual core linux pc for general stuff like writing text docs, email, youtube, irc, facebook, I have to say I highly enjoy my time on this computer, got compiz, dosbox, amiga via EUAE, most linux games, many windows games that behave in wine, alot of sound/music stuff I still tinker with. Almost all software I have used or liked since I started with computers is on this. I also dual boot aros on it but still prefer the linux side for most of my geeky adventures... This machine also boots windows xp if I need it, which I rarely do...
Thats my "modern" setup. My retro setup, which used to consist of a c64, an amiga 1200 and a color computer 3 is now gone, in favor of virtual workalikes on the linux box. More comfortable room now. But I miss the old girls...