Apple really should make this option more accessible through Dock preferences. It defaults to this view when the Dock is not on the bottom anyway, so there would not be a whole lot of effort required to do it. The 3D dock just feels awkward for a guy like me that has it hidden all the time. Something that bulky doesn't look nice appearing out of an edge of the screen.
Also, as a speed-up trick, with a Finder window open, go to View > View Options and uncheck "Show icon preview." This will make the list and column views of Finder only show file type icons, not the Quicklook preview of the file. For a slower 5400 RPM hard drive, this can have a very noticeable effect.
Finally, in the Desktop and Screensaver System Preference pane, you can toggle the translucency of the menu bar on and off. I don't know how much of an effect this part would actually have, though maybe some since the MacBook lacks a dedicated video card. If your background is dark enough, it's not even noticeable whether it's on or not most of the time, so why waste your resources having it on?