So I've decided to upgrade my Aspire m1641. I've picked out the BFG GTX 260 and was recommended the Sonata III 500 case/psu combo. I have 3GB of ram currently as well. Is this a good combo? I'm also curious: what exactly does "HDMI Capable" mean? I saw the two DVI ports on the card but not an HDMI port?
The GTX 260 is generally quite overpriced. You can get the same performance with much greater power efficiency and more modern features(like DX11, 3 monitor support, ect) for significantly less money from an HD5770.
I agree with this. The Antec 300 is a good case, and the OCZ PSU's are pretty decent too. I'd be more comfortable with that setup personally. The OCZ power supply is a little higher wattage, and I think better Amperage on the 12V. Hard to zoom in on the pictures for sure. The antec unit was 13A on two rails, think the OCZ showed 17amps on each rail. Anyhow, the OCZ unit is modular, which can help quite a bit with keeping cable clutter to a minimum.
Although I use an SLI GTX260 setup (and love it) the ATI 5770 is comparable performance wise, and is cheaper. Plus it's a newer generation card that supports DX11 (and from what I understand does run cooler, quieter, and use less power). Though you will have to deal with ATI drivers, which sometimes are fine, sometimes aren't. LOL
You might also consider your motherboard type. Does it support SLI or Crossfire? There could be an advantage with going nVidia or ATI if you want to run two video cards at once some day in the future. But that's all about preference and possibly leaving more room for less expensive upgrades later.
The Sonata has an EA500 which has two 22a +12v rails with a max power rating of 408w. The OCZ psu I linked has two 25a +12v rails maxing out at 450w. It's slightly better and modular like you said but both are more than competent.