Dells have a good bang for the buck - just be sure to opt for 2-3 years of service contract unless it is disposable (computers can and do fail) or you are a genius
For some of the best pricing on a Dell - you need to watch fatwallet.com and the hot deals forum for good deals on these. But you need to be able to pull the trigger when a deal comes out as they can last between a few hours and no more than a couple days - but you can occasionally score well.
I had needed to upgrade my work laptop for a while and wanted best bang for buck. With a responsible budget around $2K I could get something OK but I new sooner or later a $750 off $1500 laptop coupon sould come along so I kept in the loop and when it presented itself in June 05 or so, I was able to spec out a $2600 laptop, stay well below my self imposed budget (public entity - trying to be responsible), and essentially save the city I work in some coin - just being responsible about it. Sure, Dell hates me from time to time
but WTH?