My 2 cents...
I run a "Dell Powered" IT shop for a small business. About 100 employees. I've been places that use just about every type of PC you can name. Dell to me in quality is above average, but not perfect by any stretch. I do love Dell's engineering and design. Compared to HP, who's machines resemble slapped together mom'n'pop shop computers any more, Dell's are very well designed. I will continue to use Dell mainly because there are no suprizes when I get a Dell computer. No funky hardare, no funky software, and they work 99% of the time. On a 1720 I just recieved for a co-worker, the power supply was no good. 48 hours later I had a new one and easily shipped the bad one back. Can't complain about that at all.
I currently order and configure about 2 or 3 dozen new computers a year. I'll stick with Dell because of the service they provide and the solid machines I get delivered time after time, with no shocks or suprizes.
BTW, I do order some components seperately from Dell's web site. For example: I think they charge WAY to much for memory, and some other parts. It's just too easy to order as minimal memory needed and pay 1/2 at newegg or some other place. Then save the memory taken out for another machine later to boost it up.
For my personal machines, I build by own from scratch, not because I can build better, because I find it fun. For my laptop, I've owned Sony's, Acer's, HP's and a few odd named ones. Today I buy nothing but Dell and have been pleased with each one. My current selection is an XPS 1710, w Inspiron 6400s (one for the kid, one for other stuff) and a new 1720 for my wife which she throughly enjoys.
Basically don't fret, you got a good machine from a good company. If you run into problems, call them and be patient. Or post your issues here and a lot of nice folks here will be glad to help you out.