I have a variety of computers with some being ancient and others just being gracefully old. Most of them serve purposes though...
My main machine
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AMD Athlon 1800+ overclocked to be a 2400+
Radeon 9600 video card
Asus A7N8X ver 1.0 motherboard
1 Gb Ram
-- 6 years old or so --
My main machine has held up well running Windows XP. Granted, it can only play newer games at the lowest settings, but it works for most everything else just fine. However, the motherboard in particular is not supported in Vista. Therefore, I will upgrade this system soon.
Laptop
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Compaq Presario v5303nr
AMD Turion 64 ML-28 1.6GHz processor
AMD Radeon m200 integrated video
Windows XP, but Vista capable
-- 2 years old --
Other than the memory, this system should run better than my desktop. However, it simply serves as a valuable laptop for when I am not at home. I have the Vista install disks as provided by HP however I have yet to install them. The memory is simply too lousy for Vista and I haven't gotten around to upgrading it yet. Also, the integrated graphics borrows some memory for itself which would make the Vista experience even more lousy.
Laptop -- Testing
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Compaq Armada m700
Pentium III 700 Mhz processor
ATI graphics (Rage?) with 4 Mb (!!) memory
512 Mb ram
Ubuntu Linux
-- had for 3 years, is 8 years old --
This is a rather thin and light laptop which is simply out of date by today's standards. No trackpad, just one of those weird joystick track points. However, it works well with Linux and with the Netgear wireless card I have. As stated, it is a testing laptop for Linux so that my digital life doesn't come to an end if something wonky happens with that OS. However, this laptop does have a dead battery... the nice thing is that it has the same power adapter as the laptop above.
Desktop -- testing
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AMD K6-3 400 Mhz
Voodoo 3 video card
384 Mb memory
-- a long time??? --
This desktop would be a decent server except for the fact that it would take electricity if it was on. Also, I'm not sure if my ISP would be too happy with me having a server. Thus, this computer is sitting at the moment. It has Ubuntu Server edition on it though...
I have some other digital devices that might count as computers... those being a Nokia n800 and a Dell Axim x30 High. However, since they are not computers per say, I will exclude them from this listing.
I found that having a purpose for each device is vital. If the devices do not serve a discrete role then they are likely to be ignored. Otherwise, as you can guess, I am behind on the upgrade curve. I will eventually choose a desktop machine that will serve me for years to come... once I figure out what to purchase.