Intel i7-3960X CPU @ 3.30GHz, 16 GB RAM, SSD SATA 3 - 480GB.
use EXCEL 95 on it.
Luckily my Acrobat XI, AutoCAD 2012, Alibre 2012, ... performance better than the previous version.
Thankfully due to Moore's law your computer hardware gets enough faster in any given timeframe to cope with the fact that the software in that timeframe is getting slower (and this is why most people don't notice).
But the key thing here is that if you upgrade your software and never upgrade your hardware, after a while it's gonna get painful.