from what you say .... sounds to me more like you want a desktop
pound for pound a laptop still isn't anywhere near as powerful as a desktop..... nor is it as upgradeable.
your idea of an upgrade to 1Gb is virtually the ONLY upgrade option available (a new HDD is the other) for your laptop.
for less than your original �1000
http://www.meshcomputers.com/Default.aspx?PAGE =PRODCATEGORYVIEWPAGE&USG=APPLICATION&ENT=APPL ICATION&KEY=227079
(just an example)
you can get a quad core monster that will run crysis, bioshock .... or any of the latest games (which ARE incredible to look at) ..... on a 22" screen ... with surround sound .... blah blah
it will eat video editing (in real time) while at the same time still having enough left to run dreamweaver.
The second half of your question .... don't be worried about getting a slower processr ... now - anything over �500 will knock the spots off of your "old" machine.