Modest Linux Server

So while I am waiting for that hard drive caddy to come in the mail, I figured I'd reflect on what I have running right on my primary server right now. It's a modest server running Ubuntu 6.06 on the following hardware:

AMD AthlonXP 2.2Ghz
RAM 1.5GB
SATA Hard Drives X 2 @ 330GB/ea
IDE Hard Drives 1 X 80GB, System Drive 1 X 20GB

It handles my requirements just fine. I don't know how many users it would take until it got 'bogged down'. The list below is everything I am using it for and have running on it all the time.

Apps Served
==========
-SMB File Server (Samba)
-Apache Web Server (LAMP)
-Wildfire Chat Server
-VSFTPD FTP Server
-CITADEL Groupware Server
-SSH
-Folding @ Home (no rest for the CPU)

The next hardware upgrade will be 2 X 500GB SATA hard drives. I will set them up to mirror each other like the 330GB hard drives are currently configured. So yes, I will be adding a terrabyte of storage space, but I will only use "1/2". I will be looking into adding a DNS server to the app list.