My question is - what is the best way to approach the triple monitor setup. I'd like the 7800 to power just one (main) monitor. Then i'd like the other two monitors setup on left and right of main monitor. I looked around and found some dual DVI PCI cards, but they're pretty pricey for just a PCI card.
There is an excellent forum on this subject Widescreen Gaming Forum. The adaptor lewbaseball07 mentioned is made by Matrox, it's called the triplehead2go. It'll allow you to run up to 3840x1024 for "surround gaming". There's support for well over 100 titles...But, you're going to have a hard time running that resolution on any newer games with that graphics card. 3840x1024 is almost 4 mega-pixels 8O But it will also let you run at lower resolutions.
The forum I linked to above is the source you need to find your solution.
BTW- it uses an analog VGA connection, so the DVI concern isn't relevant for this solution.
OH! Wait! In that case, this may not be the most elagent solution...When in Windows, maximizing an app will maximize it to all three screens. I would think you may want to disregard my post, I thought you were seeking "surround gaming".
So going back to your original question, you have the right idea. And yes a PCI card to do what you want will be expensive, simply due to supply and demand.
I have a HP Pavillion dv6 7010us with two dell 19" LCD monitors and a new Samsung 32" flat screen. I have a SIIG USB 2.0 to VGA converter from when I just ran dual screens on my dell monitors, but it ended up working for my triple monitor display. I have been researching how to do this for the past couple of days and nearly gave up. I did not want to go buy a graphics card because I heard that you can do it without one. I ended up just screwing around with my settings and accidentally set the monitors to the triple display setting. I have a USB 2.0 SIIG adapter that runs a VGA to my main monitor, a VGA going to my secondary monitor, and a HDMI going to my TV. Every time I tried to change the settings it would revert back to the old settings until I set the TV to my main display and it automatically made my other two monitors my second and third display. Its been working great.
I would suggest that before you buy a new video card (unless you needed one anyway) that you check your settings and ensure that it wont work as is.