I haven't bought a name brand computer since 1983. I always buy parts and make my own. I usually buy from
www.newegg.com, they usually have the lowest prices and have a great customer service rating from three or four online rating sites. We use Compaq/HP at work but have started buying Dells this year. HP is still strugling and Dell can be tough to talk to. I had to become Dell Certified to be able to call in and get warranty service on our PCs. Oh well it wasn't my decission to switch to Dell.
I buy a lot of stuff from BH Photo Video with great results. Their prices are kind of high on some things. I buy a lot of my Epson expendables from Atlex.com. Another good supply site is Inkjetart.com. Their prices are s little higher that Atlex.com but if you buy over a certain amount the shipping is free and that makes a big difference sometimes.