Build advice sought

[Roger H. Goun]

I'm looking for advice on components for a new server that will run
Ubuntu 12.04 LTS. Most of the workload will be Postfix, Apache, and
MySQL. Web and database activity will be light. The mail server will
support a couple of dozen users. Storage will be a RAID 1 with 2 TB of
mirrored space and an additional drive for backups. Case will be a
medium tower. Two Ethernet ports are required. Budget is around
$1,000.

The Asus motherboard that I built into half a dozen Sandy Bridge
systems in the past couple of years is no longer available, so mostly
I'd appreciate CPU and motherboard advice. Inexpensive integrated
graphics would be nice, since the machine will never leave VGA text
mode. I'm also interested in your thoughts and experience on whether
dual power supplies are worth the additional cost for a small server,
and any other considerations you think are important that I haven't
mentioned.

Thanks.

-- Roger