I have a I-700m and the Latitude X300. I am selling off the Latitude X300 for 3 reasons. First, it is too delicate; the X300's and 300m's have all suffered from flimsy LCD screen lids, leading to the discoloration "smiley face" effect that plagues them. There are TONS of messages on the DELL forums that touch on this issue. I have already had DELL replace the LCD once and I have to keep it in its own case so not to recreate the issue. Second, the screen is better in clarity and sharpness, and the widescreen makes it a must have for multi-tasking by having 2 windows opened side-by-side. Third, I prefer having the drive built into the notebook itself; carrying the X300 with the D-Bay module is cumbersome at times, especially when desk space (i.e. at school, or plane, etc) is at a premium.
Finally, the 700m isn't very photogenic in my opinion, looks much better in person,
and it's footprint is a little less than the X300 and weighs not much more. The X300 plus D-Bay (DVD/CDRW Module) weighs about the same as the ALL-IN-ONE 700m.