Ok, it's been awhile since I have built a PC and I am not up to speed on what the latest and greatest is. I currently do not even own a desktop, I do all my work on my quad core Sager NP9262 notebook w/ 6 GB of ram. I need to upgrade to a more powerful computer that can handle heavy use of design applications with multiple programs running at once.

Ideally I would like to be able to have photoshop, dreamweaver, fireworks, firefox, and bridge all running at once smoothly with no system lagging. I have decided it is in my best interest to build a desktop PC rather then purchase another laptop as desktop parts tend to be cheaper, more upgradable, more bang for my buck, etc. Since I am building the system from scratch I figure that will also save me some money and allow me to get a better performing system for the same price as a pre-built desktop PC with lesser performance. I am hoping to do this for $600-700 but not sure if that will be possible. I know RAM is the most important factor for the PC to perform well adobe programs but not sure what's out there beyond that that might drastically improve performance for the type of use I am planning. I need some advice on what I should focus on for optimal performance in the areas mentioned and some specific hardware I might want to consider. Obviously with my budget I know I will not be getting the latest and greatest but I can probably get the next best thing for a decent price from different online retailers such as newegg. Any guidance would be appreciated.