Alright, i know I am repeating, but I havn't found anything out there in the search, all are ether AMDs or have unmetered lines, I a thinking somewhere along the lines of 500-1000 GB of bandwidth or 2-3 mbs.
With full IRC capabilities, and without half of the TCP / UDP port range blocked off. ICMP is important to have (if rate limited heavily).
there are many companies that offer what you need, in fact there are open threads right now on this. ev1servers.net, versehost, fdcservers, dslglobal.net, www.blacklotus.net,www.server4you.netwww.southo.net etc etc etc
most if not all of these guys don't block any ports and nullroute IPs upon ddos attacks
Check serverpronto.com - they have a server linked to the DALnet IRC network. They're setup fee is something like $99 but then the monthly rate is only $30/mo. Last time I checked they were offering unmetered traffic and IRC is permitted.
The setup fee sucks, but the monthly rate is nice.