Not much of a hardware requirement
For Blizzard games, I have always purchase the full version and I own them all in fact. I've also had the cool experience to beta test Diablo before it went gold back then. Even though they are mainly drawn in 2-D, the graphics from any Blizzard games are fantastic (IMO). Great games that are well developed, so I guess I'll order my copy of Warcraft III via the internet as well.
Got this from Blizzard's website (latest and greatest computers not required if you look at the requirements below, but PLEASE do no play using a 28.8 modem ... nothing less than a cable speed connection online for the sake of other players' sanity... thanks.

):
What are the system requirements?
Windows 98/ME/2000/XP
* 400 MHz Pentium II or equivalent
* 128 MB of RAM
* 8 MB 3D video card (TNT, i810, Voodoo 3, Rage 128 equivalent or better) with DirectX 8.1 support
* 700 MB HD space
* 4X CD-ROM drive
Recommended
* 600 MHz processor
* 256 MB of RAM
* 32 MB 3D video card
* DirectX(r) 8.1 compatible sound card
Multiplayer
* Low-latency, active Internet connection rated at 28.8 Kbps or faster. LAN play requires TCP/IP connection.