Unless you game you don't need a video card.
1gb will suffice for an office pc running XP, but 2gbs will not slow up as fast if you have alot of programs running at the same time.
As far as hard drive, I would look at what they cost. ANYBODY can install a hard drive in a pc. Its like putting legos together, really. 250gb ($50) and 500gb ($100) are both dirt cheap. If dell has them overpriced you can just install one when you get it.
But...here's the god's honest truth...Its more about software than hardware. If you take care of a celeron 1.5ghz w/512mb of ram, run virus checks, spyware checks, defrag the hard drive, once a week or so, it will run better than a Quad core with 8gbs of ram that isn't taken care of (ridden with spyware, useless background processes, programs you don't need, ect), at least when it comes to general usage like browsing the web or using microsoft office.
The truth is that the difference between hardware is most noticable because of the software you run. If you take care of your software, even slow hardware will perform fine. There are limitations to hardware, of course, but most people never see the full potential of moderate hardware because they don't take care of their software.