I've been using Dells since Dell started, and have always had good results.
I use them for Aces High, and they work fine with good performance as long as I'm using a $125-$150 graphics card added in.
I think that Dells are great performance for the price.
If I were buying right now, I'd get:
Dell Inspiron 660 is $500 (i5-3330, includes OS, 500 GB HD, 4 GB RAM, DVD+/-RW, 100/1000 Ethernet, sound, keyboard, mouse)
Thermaltake 500W ATX12V power supply is $50 (from Newegg)
Nvidia GTX 650 Ti (rated best for price range by Tom's Hardware) is $130 (from Newegg)
total = $680
What I have right now is not as good as that, and it still allows me to run Aces High with stuff maxed out and 60 frames per second (including in thick clouds in special events). (I currently have a Dell Vostro 460 with i5-2400 and NVidia GTX 550 Ti.)