i am looking for specs to build a decent ftp server (ms iis, I have versions all the way from 2000 to 2008) so softrware no problem. Need about Tbyte of storage, have uused iis6&7 so really nead hardware specs. Its only going to be used as an ftp server and desktop for me with office apps and accounting
IIS doesn't require a lot of processing power to run. It could easily run on a single-core system. What's really going to bog the system down is the reads from your hard drive(s); particularly if you're also running your office apps on the same drive. I'd really recommend running two separate systems. If that interests you, list the specs of your current system and we could probably recommend either keeping your current system for office apps, or building a new system and using this one as your FTP server.
If that's absolutely not an option, then I'd recommend just about any mid-range dual-core system with 4 Gig of RAM (depending on which ServerOS you intend to use). Hard drives, I'd probably recommend at least three. One for your OS/Accounting/Office Apps (whatever size you need) and two 1 TB drives, mirrored for your FTP content.
Edit: Also, look to my system specs below. I'm running Server 2008 w/Hyper-V. I have two virtual Server 2003 systems (IIS and SQL) as well as either an virtual XP or Vista system running.