Advice sought on moving to AMD64

[Rory Campbell-Lange <rory@campbell-lange.net>]

How hard is it to use Debian AMD64?

I run about 15 Debian servers for various clients. These are all 32 bit
machines, mainly dual Xeons or Pentium IVs; we use Debian on our Apple
ibooks too. All of our machines run stable + a few things from testing +
occasionally something from unstable.

We are getting ready to purchase a machine for a web application
prototype. I won't go into the nitty gritty of what the machine is to be
used for, but suffice it to say that we want good Postgresql 8.x read
and write performance and enquiries on the postgres list brought us
here.

Basically, I'm keen not to make a lot of work for our team by supporting
unusual hardware. However, we are keen to experience the benefits of
using 64bit! Does Debian AMD64 have installers, eg netinstallers? Does
AMD64 have stable, testing and unstable package trees?

Thanks for any comments,
Rory

p.s.
Our standard environment includes:

    Apache 1.3x/Apache 2.x
    PHP4
    Python 2.3/2.4 including all standard modules
    Perl including all standard modules
    Postgresql 7.4/8 (I believe I can compile the latter from the debian
    source packages myself)
    Exim4
    screen
    netfilter/iptables
    etc.

One possible configuration we are looking for is as below:

    Motherboard        : Dual AMD Opteron,[X2881G2NR],AMD8131, 
                         Up to 3x PCI-X,S-ATA Raid,2x Gigabit LAN
    Chipset            : AMD-8131
    Info               : 5 x PCI (Total); 1x PCI-X for 1U and 3x PCI-X for 2U; 
                         Graphics Slot = None
    Ports              : 2xUSB V2.0 [Rear],PS/2 Kb, Mouse,Serial,Parallel
    Maximum            : RAM     16GB using 8 x 2GB
    On-board Graphics  : Integrated ATI 8MB Rage XL
    Std HDD Controller : IDE UDMA 100 (Primary & Secondary
    On-board SCSI      : None
    On-board RAID      : S-ATA Raid (Raid 0, 1, 10, 4 drives) Silicon Image 3114
    On-board LAN       : 2 x Broadcom 10/100/1000 Gigabit Ethernet
    On-board Audio     : None
    CPU                : 2 x AMD Opteron 242 1.6GHz (2-way) - 1MB Cache
    RAM                : 2,048 MB Total using 4 x 512MB PC3200 DDR Registered ECC 
                         (Use Only In Pairs)
    Chassis            : 2U C215S, 8x H-Swap SCSI Bays, Slim CD and FD bays, 
                         660mm, 2x 64bit PCI, 510W (Black)
    Rail Kit           : Telescopic Rail Kit included with case
    RAID Controller    : LSI MegaRaid 320-1, 64 Bit PCI, Ultra320, 64mb, 
                         Single channel, Raid levels 0,1,3,5,10
    SCSI HDD           : 6 x 36GB 15,000 rpm Ultra320
    Ethernet           : 1  2 x Broadcom 10/100/1000 Gigabit Ethernet 
                         on-board motherboard

-- 
Rory Campbell-Lange 
<rory@campbell-lange.net>
<www.campbell-lange.net>