G4 400 vs Mac Mini

I need to set up a new home server as my current PPC G5 powermac is being relocated to more important tasks. I have a old G4 400 with 700+ meg of ram in at my disposal or I can grab a new Mac Mini. I know that if I went with a mini I will only have one NIC which is a issue because currently the server performs auth for the adsl line then spits it back out over the other nic with DNS and lots of other services. So thats a problem, also, the mini has drive limitations with only one internal drive but I'm not sure of the upgrade path and how other people have put in new drives. I was thinking of looking for a SATA controller that works with the mini then building some kind of SATA raid or at the least, going with firewire. I like this SATA solution with the mini because of speed and because I do need to buy new drives (want 1TB of network space minimum). Question is, would the G4 keep up with 1+ TB of IDE storage and also do simple firewall/dns at the same time? In the past, I have run web services on it and it struggles to generate pretty standard php pages in less than a second. Should it be fine as a storage box? I guess I would rather go with a mini and have everything central accross one server but if I had to use the g4 for the two nic's to bring in the connection it would be ok (but really not the best solution). Anybody used third party NIC's on minis before, its only a 24mbps connection so I was thinking about a USB NIC dongle as I have heard of them being used before. Any help would be great guys! Thanks, great resource!