Very Important: Dell Inspiron 570 can be overclocked if you are using right processor! So, I570 is the good PC for all, for starters it is OK for basic tasks, just make sure you get more RAM, 4 GB minimum, you can upgrade to even 16 GB, but this is way overkill, so 8 Gb is the sweat spot. Next processor. So far the fastest one reported to work in Inspiron 570 is Phenom II X4 965 BE (if you are up to upgrading please visit Dell Support forums for more info, type Inspiron 570 into search box and look for posting by me and OCMusicJunkie, if you have questions, just post it there). The end result - I am playing BF3 at medium settings (could be better, but I spent too much already), all applications run fast and easy, the best PC for a $$! What else do you need?!
The only con is that you have to work hard to make this PC a good one, it is not so easy.