Some comments about that configuration below:
Mainboard: Nothing extreme, it’s a solid mATX mainboard featuring 2 IDE channels and 4 SATA channels. The builtin graphics is good (for being integrated that is) and is pretty much equal to a Radeon X300SE, if you want later on there’s a PCI-Express slot available so it shouldn’t be an issue. You also have two PCI-slots and one PCIe slot for controllers cards or whatever you want to add although I do belive that the PCIe slot will be blocked by the video card if you decide to get one later on. It also offers HDTV (component) and DVI/VGA output which may be a nice little bonus for you americans since HDTV-sets is a lot more common than in Europe. There’s one issue with this mainboard though (actually the SB450 southbridge in general) and that’s USB 2.0 performance. It’s not the greatest around (it works well for cameras and other input devices) but it may be a bit slow for external HDDs (around 15-20mbyte/s). I have this mainboard myself and I cant say that it bothered me much and I do like the fact that it doesn’t use the nCrap chipset. Oh yea, it also offers HD Audio
Case: In order to stay within budget I had to go with a bit cheaper case, it offers 5 3.5" drive bays and also 5 5.25". It’s not exactly what you’ve asked for but I think it’s the best case you can get for this kind of money and its way better than what Dell offers.
Monitor: Scanning newegg and ncix I found that this monitor seems to be a good bang for the buck, I havent seen it myself though but it looks good on the paper at least
HDD: Nowdays 250Gb is the smallest drive I’d recommend you do get due to space/performance/price. Also, since originally planned on getting a 160Gb drive (and still use older ones from your old computer) you’ll save one bay (I figured you have a 80Gb drive in your old comp probably)… =)
As for brand Hitachi T7K250 has gotten very good reviews regarding performance and there hasn’t been any reports of bad batches or so (no flamewars about this thanks).
PSU: FSP makes good value PSUs (you’ll find their PSUs in many branded computers) and this perticular model offers a 120mm which helps ventilation greatly while still keeping noise at a comfortable level. Silentpcreview.com should have a few reviews with FSP PSUs if you want to read up a bit.
RAM: We all love Corsair dont we?
CPU: Well, we had a budget and it’s a bit slower than the dual core CPU in multithreaded applications although faster than both CPUs when it comes to single threded applications (games, compression applications etc).
As you’ve said yourself, you probably need an additional controller card if you want to make use of all drive bays…
If you still wanna go Intel I’d say ASUS P5RD2-VM and Intel Pentium D 820 although you would break your budget by 20 bucks or so for pretty much the same thing (faster USB 2.0 performance though). Keep in mind that P5RD2-VM uses DDR2.