Hey Moby,
Welcome to PC101!
Well, the Dell was a gift from my brother and it was the fastest way to go since my computer was making weird noises that turned out to be its last breaths! :p
In the old days... when we lived in the same state...he'd build me one from scratch... it is definately the best way to go!
Like most things (cars, houses, furnature, whatever) it's the labor that costs the most! It's much cheaper to buy the pieces and fix/put it together the thing yourself!
ED