A few bits of information to the
clueless....
One, Dell uses quality parts. Not cheap motherboards, power supplies, hard drives or RAM... GOOD NAME BRANDS!
IIRC, MSI makes Dell's mobos. Yes, they are altered slightly... the power supply and motherboard plugs are the only things altered and you can get adapters for almost $nothing if you wish to change motherboard or power supply.
The case is efficient, quiet and well made. Maybe it doesn't hold 10 drives, but the hooded CPU fan does a super job of keeping things cool and quiet. And it's a sure nicer looking case than anything less than a $100 Enermax case (or something else well above the "cheapo" ugly cases.)
The OS may be included on a restor disk, but guess what? It's in its own directory! Yes, that means you can install the OS totally independantly of all the restore crap. You even have to go through the normal driver stuff Windows install would. You only get the Dell drivers (and bloatware) if you do the "restore". Install from the seperate "windows" directory, you got a totally normal install.
You get a system in totally matching black colours.
No, unfortunately, you can't overclock. For some people, this is probably for the best. Little Timmy who just discovered overclocking and wants to try a 1132MHz FSB would be better off NOT having the overclocking options.
The price! Sometimes it's a darn good deal BEFORE you consider the price of software! When I bought my P4 machine over two years ago, the $1000 Canadian it cost was worth it for the hardware alone! But I got Windows ME and Office XP on top of that! There's no way I could have put this system together with the software for anything CLOSE to that!
Speaking of price, it's nice to have financing options. You can even pay it off early with no penalty.
And the service... woo.... my monitor started displaying some flickering lines on the bottom of the screen, so they replaced it. The new monitor was a complete fuzzball (fuzzy, fuzzy) and they replaced it again - this time with a free 2x upgrade to a Trinitron. Both times they were shipped overnight. I actually had three Dell monitors sitting in my living room until they came to pick up the other two!

I would have been wise to get the extended warranty but I let the service lapse so I'm on my own now. Not that I lack the technical prowess (I've built systems for years, even a Shuttle box recently.)
So, while maybe not perfect, I would take a Dell over any other pre-built system. Absolutely. Quite often over a self-built rig!