It sounds like you are right on with the 6000. Anything else would be overkill for what you are doing as long as you don't expect it to to play new 3d games well.
In some cases, there could be a different model of dell laptop that uses the same form but has different internals but will work in a variety of models. For instance I just ordered a new battery for my 8600, but it can also use the D800...
The FSB on intel chips these days have a quad pumped FSB. Therefore, the real FSB is either 100mhz of 133mhz. Your ram on the other hand can run at different FSB ratios to acheive 266 or 333 ect... Also, they don't make pc3200 in...
Now that there are just as good of vid cards in laptops, there is really no reason to get a desktop besides lower price. Laptops exceed in just about every other category
Believe me, you NEED a screen that big. I built a theater in my basement with an HD projector and built a screen that is 130" widescreen . 100% neseccary
Dell's service I have found is better than most, but still room to improve. I just have a very hard time chatting or talking to anyone there because I know way more about computers than most of them ever will, then they try to speak to...