Given the gaming bit then, would one of the higher end Dells that you linked to be a better bet than the Aldi one? I dont do much gaming and, TBH, am pretty crap at it anyway... I just enjoy some of the graphic blood and snot to vent frustrations!! 
You got the screen already?
Gaming aside, my needs are similar (even though I run Visual Studio occasinally).
I'd be looking at Core2 Duo 2.0 - 2.4G, 2G RAM, 965 chipset, any video does me as not gamer, small HDD, as use (the OOF
) server for storage.
Got a 19" LG flatscreen. Not the fastest of response times but enough for what I need. Nice and clear and sharp images.
So, depending on the chipset, the Aldi one seems OK-ish?
What would your chipset recommendations be, from worst to best?
generally, chipset wise, stick to Intel, and higher the number the better.
Personally I'd go for the branded Dell than the unknown Aldi, plus Dell is cheaper. Dell have peeved me off, and their helpdesk needs a lot of patience (don't fight it, just answer the Qs and do as they ask), but it will be hugely better than what Aldi offer.
I have a mutual hatred of anything Sony or HP, so won't recommend them.