Moogie,
first of all be sure of what you buy. The last HP and Packard Bell Computer force you to send the computer back to their service if you wanna reinstall windows because of a serial number specific to the windows release you have...
Of course you can forget the installation of linux

but thanks god there will certainly be a way to install the new windows Longhorn :]
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Then be sure that youll have what you are paying for. If a computer with a warranty of 1 or 2 year(s) is cheap, it means your material is created to work 1 or 2 year. (in fact its a statistic system : a defined number of pc must work after the warranty time... something like 85% its the most economical way to do but not the most moral)
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if you wanna use a good computer do like John Thazer said... but be prepared to pay a little more... its the price of the quality.
Personally Ill buy a new computer for 1200? with lcd/tft 19\" Geforce GT6600 256Mb 2xkinston Dual 512Mb (1Gb of ram) SLI and RAID Mother board AMD 64 3200+ s939 Maxtor SATA 200Gb 16x DVD recorder sound 24bits and whats very expensive a high silence ANTEC Sonata Box and the cherry on the top of the cake ... a disk reader (lol Im kidding it cost 7,5 ?)...
And Ill finally be able to be back to Yliakum !!!!!!!!!!!!!!!!!!!!!!!!!!
EDIT : advices :
- Nvidia (because of the linux drivers : never forgot - even if you swear today that windows is the best - that you must be able to have the choice the day you will need it)
- dont forget the cpu clock isnt the most important the 64bits system will be very important very soon (especially if you are a linux user ... but i know its not the reality). The 64bit releases of Windows would react differently... I wont advice you the peanuted peanut (Im old enough to censure myself) of Windows Longhorn but 64 bit is the future
- lifetime warranty mean the material will work properly (for example kinston memory)
- 1Gb memory is required
- dont forget the dvd recorder