Emachines are complete shit. My wife has one and I just want to throw it into the trash and build her a new one. But she loves it sooooo much.....
They're impossible to find parts for, support for it is non-existent, (good thing I'm a techie and can fix anything that broke on it or we'd be hosed) and you can't upgrade it either. The case design and the MOBO for the majority of them just doesn't allow it.
Now, about Dell....
I absolutely hate them with a passion as well. I can't stand their "tech support" dept. I just can't stand talking to them and trying to understand "Ted's" english. Their products are more flexible with it comes to upgrading them, but when you first buy a dell, watch out! You pretty much have to do a clean install of windows to get rid of all the "get free MP3's" "dell support" "dell service center" icons that automatically pop up on the desktop.
So my recommendation, build your own system man. Build your own.