Mako321 said:

You'll love it. Awesome keyboard, TrackPoint, solid as a rock, HDMI output, easy as Heck to work on, matte screen for less glare, and the screen size and resolution were made for each other.
As long as the new RAM you get is the same speed it will work fine. It is best to have a pair of matching DIMMs, so if you're just going for 4 gigs get another 2 gig stick with the same characteristics as the stock RAM. I upgraded my x100e to 4 gigs, and that's more than enough to handle TF2 and heavy web surfing.
The x100e can handle 8 gigs of RAM, not sure about the x120e but it might as well. That's a crazy amount of memory to stuff into an 11.6" laptop, but you're guaranteed to never need any more. In my opinion 4 gigs is the best balance between cost and elbow room as of right now.
The only gotcha you might run into is the 32 bit OS, if that's what it shipped with. If you can get a hold of a 64 bit Windows 7 install disc, you can make an installation thumbdrive, delete ei.cfg, and install using the Windows license under the battery. (Vista and 7 licenses are tied to the edition of the OS, not which architecture it's built for.)