re: buying vs. building
i would say it all depends on what you want to get in to. If you have an interest in putting together a machine then i say go for it. You get to choose all the parts and what you want to spend etc. and what you are designing it for. BUT with this path you also get the potential headaches of building a machine and when hardware doesn\'t get along it can really be a mind
****. but having said that if you do your homework in advance you can minimize those issues.
Buying from say dell is nice if you want a machine thats going to probably work right out of the box. There isnt alot of money to be made in Hardware sales. They ususally make the money on software. So if they give an option to opt out of sopftware that always a good idea. you can also find it somewhere else. But this is nice because if there is an issue withthe machine they will fix it / replace etc.
It really depends on what you want. You\'ll get more for your money if you build it IMHO but weigh that vs. stress level
hope this helps