While I have no experience with the Dell Dimension 3000, I can provide some information about the video setup. Intel Integrated Graphics 2 is not a ''true'' graphics card...it is a chip on your motherboard which ''simulates'' a graphics card.

The differences:
* Intergrated graphics (IG) cannot be upgraded, removed, etc, as it is not an actual graphics card. However, it can be disabled should you install a graphics card.

* IG work by using your system resoures (primarily your RAM) to simulate the effects of a graphics card. Since IG use your system resources, your computer won't be quite as fast as someone with a real graphics card, but most don't notice a big difference in speed and response time.

* When using IG, Windows and applications will not recognize your full amount of RAM. For instance, if you has 512MB of RAM, and you have 128MB integrated graphics, your BIOS will recognize 512MB, but Windows and apps/programs will only recognize 384MB. This can become a problem if you are running programs that require a certain amount of RAM.

* You will not notice a difference between IG and a real graphics card when browsing the web, typing a documents, or playing solitaire. However, depending on how much RAM is allocated towards graphics and how much total RAM you have, window animations may be slower or choppy. Also, Microsoft is recommending real graphics cards for anyone who wishes to run Windows Vista, to be released the end of next year. Those who have integrated graphics will have to run Windows in a reduced graphics mode.

* Playing DVDs and videos are OK with IG, but a trained eye will see that the quality isn't quite as good. Also, momentary freezes in the video, choppiness, etc are not uncommon, especially during fast action sequences. However, processor speed and total amount of RAM also contributes to this.

* Basic games will be fine, and even more advanced games can usually be played. However, you will experience problems. The quality on most games will be lower, especially in fast-paced action/adventures. Also, some games require a true graphics card, so you won't be able to even play the game. (And most stores won't let you take it back if it's been opened.) Thus you should make sure of the requirements, and even download a demo to make sure it will run without problems.
Over all, integrated graphics are a nice, cheap alternative to having a true graphics card. If you are planning on using the computer for daily tasks and only occasional gaming and video watching, integrated graphics should be sufficient. However, if you are planning on playing more advanced games, are a stickler for detail, or wish to use your computer as a hub for your entertainment needs/desires, it would be wise to purchase a standalone graphics card to increase overall performance.

Hope this helps,

P.S. I'd like to note that the Dimension 3000 lacks AGP and PCIe ports, which limits you to the older PCI graphics cards. However, PCI graphics cards are still widely available (click here for one such card available from best Buy), and will offer a nice boost in your video and overall system performance should you decide to install one.