What's your impression of the smaller 1U servers that have started to appear on the market?
I've used a few manufacturers' 1U (1.75") servers: Compaq's ProLiant DL360, Dell's PowerEdge 1550, Hewlett-Packard's (HP's) HP NetServer LP 1000r, and IBM's xSeries 330. These servers seem well suited to just about any purpose—as a Windows 2000 Active Directory (AD) domain controller (DC), a DNS server, a RAS server, or a Web server.
The servers I've used limit storage to three hot-swappable hard disks, except the xSeries 330, which has two hot-swappable disks. (I don't understand the rationale behind three hard disks, unless you use two disks as RAID 1 and one disk as a hot spare.) Only the ProLiant DL360 has an integrated RAID controller; if you want to use hardware RAID with any of the other products, you must use a PCI slot. Each of these machines has two PCI slots, except the HP NetServer LP 1000r, which has only one. Each machine ships with two integrated Ethernet controllers.
Of the four servers I've tried out, I preferred the PowerEdge 1550. The performance was good and the price was right—about $4200 for a configuration that included dual 866MHz processors, two 18GB 10,000rpm hard disks, 512MB of RAM, a Dell PERC 3/DCL RAID controller, and a 3-year, 24 * 7 onsite warranty. Similarly configured servers from the other three manufacturers cost almost $1000 more but didn't include enough additional functionality to justify the expense.